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A TEXT-BOOK 

OF 

MEDICAL CHEMISTRY 

AND 

TOXICOLOGY 



BY 



JAMES W. HOLLAND, A.M., M.D. 

PROFESSOR OF MEDICAL CHEMISTRY AND TOXICOLOGY, AND DEAN, 
JEFFERSON MEDICAL COLLEGE, PHILADELPHIA 



FULLY ILLUSTRATED 



SECOND EDITION, REVISED AND ENLARGED 



PHILADELPHIA AND LONDON 

W. B. SAUNDERS COMPANY 

1908 



«\> 



U8HARY of CONGRESSJ 



i wo Copies rtecMive*" 

SEP 9 WOb 

vOujff K>it tillf* 

OUSS «• AXc, no. 
SOP Y a. 



Set up, electrotyped, printed, and copyrighted April, 1905. Reprinted January, 
1906. Revised, reprinted, and recopyrighted August, 1908. 



Copyright, 1908, by W. B. Saunders Company. 



PRINTED IN AMERICA 



PRESS OF 

W. B. SAUNDERS COMPANY 

PHILADELPHIA 



! ?</J 



n 



TO THE MEMORY 



ROBERT CHAPPELL HOLLAND, M. D. 



FILIAL RESPECT AND GRATITUDE 



PREFACE TO THE SECOND EDITION 



Ix its present state the book has been thoroughly revised and 
made to accord with the recent edition of the United States Phar- 
macopoeia and the advances in physiologic chemistry. The author 
is grateful for the suggestions of kindly critics, which have been 
duly weighed and in many cases have been used. The limited size 
of the work has prevented the more extensive additions that some 
have thought desirable. While almost every page has been modi- 
fied for the better, the additions to be especially noted are those 
relating to the electronic theory; chemical equilibrium; KjeldahPs 
method for determining nitrogen; classifications of alkaloids and of 
proteins; chemistry of foods and their changes in the body; syn- 
thesis of proteins and the latest improvements in urinary tests. 

9 



PREFACE 



Ox admission to the medical college the student is expected to have 
some knowledge of physics. Experience shows that a part of this 
information — concerned with chemical questions and having toxicologic 
and therapeutic interest — needs to be refreshed and enlarged. 

The remarkable developments of physical science in recent years 
have furnished the practical sciences with working principles of great 
value, which are being applied successfully to biologic problems in 
bacteriology, toxicology, and pharmacodynamics. Cryoscopy, osmotic 
pressure, electrolytic dissociation, mass-action, radio-activity, have not 
been recognized hitherto as part of the preparatory studies, and hence 
should find a place in the medical text-book to the extent, at least, of 
a compendious statement of the principles involved. 

It is desirable that some exposition should be given of the results, 
as well as an underlying knowledge of methods. All that has been 
included within the scope of this work is little more than a foundation 
for those who choose to build upon it hereafter. This must be a growing 
class, for there is great hope of medical progress in this direction. The 
discoveries of- Arrhenius, Van t'Hoff , and Ostwald have been the point 
of departure for the biologic researches of Loeb and Pauli, and the 
medical studies of Koranyi, Hamburger, and Zikel. Those who wish 
to pursue these fascinating studies further are referred to Walker's 
Introduction to Physical Chemistry; H. C. Jones' Elements oj Physical 
Chemistry; Ostwald's Principles of Inorganic Chemistry; Cohen's 
Physical Chemistry; and Zikel's Clinical Osmology. 

It cannot be taken for granted that all beginners in medicine have 
an adequate preparation in elementary chemistry. While the number 
of those unprepared diminishes annually, it will be years before the 
assumption will be safe that the teacher of physiologic chemistry and 
toxicology in the medical school can proceed at once to the consideration 
of these practical applications of the science. 

In the present work, as soon as may be, these relationships are 
brought to the front. But the ground must first be laid by the elucid- 
ation of chemical philosophy. For lack of space, many things have been 



12 PREFACE 

omitted which would have been included had the work been intended 
as a text-book of pure chemistry. Among these may be mentioned 
the consideration of rare elements and compounds never encountered 
in the study and practice of medicine. A due sense of proportion 
requires much teaching of the essentials of medical chemistry and 
avoidance of extraneous matters which at this stage only complicate 
a study sufficiently difficult in its simplest form. 

Much of the text relating to the toxicology of mineral corrosives 
and irritants has already appeared in the chapter, by the same author, 
in Legal Medicine and Toxicology, by Peterson and Haines. The 
copious bibliographic references there given have been omitted in the 
present work — intended primarily as a text-book for students. A part 
of the chapter on the Urine appeared in The American Text-book oj 
Theory and Practice oj Medicine, edited by Pepper. Many changes 
and revisions have been made in it to bring it up to the line of present 
knowledge. 



CONTENTS 



PAGE 

Introduction 17 

Matter and Force 17 

Metrology 17 

Heat....! 28 

Thermometry 28 

Specific Heat 34 

Melting and Freezing 35 

Evaporation 39 

Boiling 41 

Magnetism and Electricity 45 

The Galvanic Current 45 

The Induction Coil 52 

Cathode and Rcintgen Rays 53 

Light 55 

Spectroscopy 55 

Polarimetry 58 

The Chemical Elements 62 

The Non-metals 65 

Oxygen 65 

Ozone or Allotropic Oxygen 74 

Hydrogen 77 

Water 83 

Hydrogen Dioxid 86 

Solution — Diffusion — Dialysis — Osmosis 89 

Solution 89 

Diffusion 92 

Dialysis 93 

Osmosis 94 

Nitrogen and the Argon Group 97 

Nitrogen 97 

Carbon and its Oxids 98 

Carbon 98 

Carbon Monoxid 100 

Carbon Dioxid 102 

Chemical Philosophy 108 

Atomic Theorv 109 

Chlorin ' 118 

Acids, Bases and Salts 123 

Dissociation 127 

13 



14 CONTENTS 

The Chemical Elements (Continued). PAGE 

The Non-metals (Continued). — Hydrochloric Acid 135 

Compounds of Chlorin Containing Oxygen 139 

Other Halogens 142 

Bromin 142 

Iodin 144 

Fluorin 148 

The Chlorin Family or Halogens 149 

Sulphur 150 

Selenium and Tellurium 168 

Compounds of Nitrogen and Oxygen 169 

Phosphorus 177 

Carbonic Acid : 191 

Derivatives of Carbonic Acid 192 

The Cyanogen Group 194 

Oxalic Acid 200 

Silicon 205 

Boron 208 

The Metals 210 

The Metals of the Alkalis 211 

Potassium 212 

Sodium 223 

Lithium 230 

Rubidium 231 

Cesium 231 

Ammonium 23 1 

The Metals of the Alkaline Earths 236 

Calcium 237 

Magnesium 242 

Strontium 245 

Barium 245 

Radium 247 

The Earth Metals 251 

Aluminium 251 

Water Supply 256 

The Arsenic Group 263 

Arsenic 263 

Antimony 291 

Tin 298 

The Copper Group 300 

Copper 300 

Mercury 306 

Lead f '. 3 2 ° 

Bismuth 33° 

Silver 333 

The Iron Group 337 

Iron " 337 

Manganese 347 

Chromium 350 

Zinc 353 






CONTEXTS 15 

The Chemical Elements {Continued). PAGE 

The Metals {Continued). — Nickel 357 

Cobalt 357 

The Gold Group 35 8 

Gold 35 8 

Platinum 359 

Cerium 361 

Thorium 361 

Uranium 361 

Molybdenum 362 

Organic and Physiologic Chemistry 363 

Ultimate Analysis 363 

Organic Formulas 367 

Classification of Carbon Compounds 371 

Aliphatic Compounds 372 

Halogen Derivatives of Methane 384 

Halogen Derivatives of Ethane 391 

Oxygen Derivatives of the Paraffins 367 

Alcohols 367 

Ethers 402 

Aldehyds 406 

Ketones 412 

Sulphur Derivatives of the Paraffins 414 

Fatty Acids 417 

Organic Acids, not Fatty. 421 

Hydroxy- or Alcohol-acids 422 

Ketone-acids 426 

Fats and Fatty Oils 426 

Esters 430 

Compound Ethers — Ethereal Salts 430 

Esters of Organic Acids 432 

Carbohydrates 433 

Monosaccharids 434 

Disaccharids 438 

Polysaccharids 440 

Cyclic Compounds 445 

The Benzene or Aromatic Series 445 

Benzene Hydrocarbons 446 

Benzene Hydroxids 453 

Oxygen Derivatives of Benzene 463 

Aromatic Alcohols 463 

Aromatic Aldehyds 464 

Aromatic Acids 464 

Hydroxy- or Phenol Acids 467 

Polynucleated Compounds 471 

Nitrogen Derivatives of Benzene 475 

Aromatic Amido-compounds and Amins 476 

Diazo-compounds 480 

Heterocyclic Compounds 483 



l6 CONTENTS 

Organic Chemistry {Continued). PAGE 

Cyclic Compounds {Continued). — Pyridin and its Derivatives. 483 

Purins and Uric Acid 488 

Ammonia Derivatives 494 

Amids, Amins, Amino-acids, and Alkaloids 494 

Alkaloids 501 

Pyridin Alkaloids 504 

Piperidin Alkaloids 504 

Pyrrolidin-Pyridin Alkaloids 505 

Pyrrolidin-Piperidin Alkaloids 506 

Quinolin Alkaloids 508 

Phenanthrene Alkaloids 512 

Alkaloids of Unknown Constitution 515 

Ptomains 517 

Toxins 520 

Proteins and Albuminous Matter 524 

Ferments or Enzyms 535 

Energy of Foods 539 

Digestion 542 

Saliva 543 

Gastric Contents 544 

Pancreatic Juice 555 

Bile 558 

Intestinal Juice 559 

Blood 561 

Milk 564 

Urine 576 



Index 629 



MEDICAL CHEMISTRY 

AND 

TOXICOLOGY 



INTRODUCTION 

MATTER AND FORCE 



Matter is anything that has weight, or anything that has 
length, breadth, and thickness; in other words, anything that 
occupies space and is perceptible to the senses. Matter is never 
absolutely at rest. If not the body in its mass, at least its particles 
are in incessant agitation. 

Energy or force is that which gives matter its properties. 
Matter is thus resolved into a " mode of motion." Energy comes 
from work and can be changed to work. Such material changes 
as are caused by the energy of heat, light, electricity, magnetism, 
and mechanical motion are said to be physical, while others are 
called chemical. For the sake of simplicity those changes called 
physical are dealt with in that branch of science known as physics, 
but as some of them are very closely related to chemical changes, 
a thorough study of the latter necessarily involves some knowl- 
edge of the physical changes. 

The universal ether is the thin elastic medium pervading 
matter and space and through which radiant energy is transmitted 
in waves. 

METROLOGY 

Chemistry deals with the properties and composition of sub- 
stances and the operations which produce change of constitution. 

Substances are known by their properties, such as color, form, 
hardness, weight, taste, odor, solubility, melting-point, boiling- 
point, and behavior in the presence of active chemicals. In 
studying the composition of a body, the properties of its compo- 
2 17 



16 INTRODUCTION 

nents, and the operation of chemical force, there is frequent 
occasion to make estimates of volume and weight, and that relation 
between the two called specific gravity. Metrology is the science 
which deals with the means employed for this purpose. 

Weights and the Balance.— In determining the quantity of 
matter present resort is had to the balance. In this instrument 
an inflexible horizontal beam is poised at its middle by a knife- 
edge, resting on a hard plate at the top of an upright support. 
The beam carries at each end a scale-pan suspended by cords 
or rods to the sharp-edged hook which freely swings from a steel 
pin. 

In one scale-pan is put the body to be weighed, in the other, 
masses of matter called weights, which have been previously 
marked according to some standard. If the gravitation to the 
earth of the body to be weighed and the weight be equal, the 
vertical index oscillates evenly over its graduated arc, and the 
beam comes to an equipoise in a horizontal position. 

The attraction of gravitation is directly proportionate to the 
mass. As the weight of a body is the effect of this downward 
force, it is plain that mass and weight will increase and diminish 
together. A double amount of matter requires a double weight 
to balance it, and one-half the weight equals one-half the mass 
or quantity of matter. 

The Chemist's Balance. — In. the ordinary balance the poise is 
not disturbed by slight variations in weight. Hence for commer- 
cial purposes, where time is to be saved and minute quantities are 
more or less unimportant, a less sensitive instrument is preferred. 
But in chemical analysis accuracy is to be desired above all things. 
For this purpose the beam of the balance is made as light as 
possible, the bearings are sharp and hard, the adjustments capable 
of being brought to the last degree of refinement, the instrument 
provided with appliances for arresting its action at will, and the 
whole enclosed in a glass case for protection from dust, for exclu- 
sion of moisture, and for the prevention of perturbations due 
to currents of air. The beam is usually divided by notches 
into tenths, so as to carry weights shaped as riders, which latter 
lessen in value as they are moved toward the center. For instance, 
a rider weighing i gram in the pan weighs .9 gram at the first 
notch from the pan, .8 gram at the second, .7 gram at the third, 
and .1 gram at the last. By this means a delicate chemical 
balance will indicate with distinctness ^ of a milligram, and 
even less weights will influence it sufficiently to show a variation 
in the position of the index as it moves over the graduated arc. 

Volume. — The quantity of space which a body fills is called 
its volume or bulk. In estimating volume, vessels of different 



METROLOGY I 9 

shapes and sizes are used. These vessels, known as measures of 
capacity, are standardized by comparison with some unit. 

Weights and Measures. — There are two systems of weights 
and measures in use among physicians and pharmacists. In the 
United States the prescriptions usually call for Apothecaries' 
Weights and Wine Measure with the common standard of the 
grain. Very rarely the decimal system, based upon the meter, 
is employed. 

In the U. S. Pharmacopoeia working formulas are given in 
the metric system. The regulations of the U. S. army require 
surgeons to write prescriptions in the decimal system. In time, 
as pharmacists grow accustomed to the easy calculations of a 
decimal system, it will probably win favor enough to supplant 
others now in vogue. 

The U. S. Pharmacopoeia Apothecaries' system of weights is 
derived from the Troy pound of twelve ounces. 

Table of Apothecaries' Weight 

20 grains = gr. xx = one scruple Oj). 

60 grains = J^iij (3 scruples) = one dram (^j). 

480 grains = £viij (8 drams I = one ounce (^j). 

5760 grains = ^xij (12 ounces) = one pound (R>j). 

In the British Pharmacopoeia and in commercial transactions 
of druggists in this country the weights used are the Avoirdupois 
pound, ounce, and grain. 

If the difference in the value of the terms ounce and pound, as 

used in the United States and in Great Britain, be not recognized, 

serious errors may be committed. As important medical works 

are printed in both countries, addressed in the same language to 

readers in both, it is to be regretted that there should exist this 

difference in terminology where uniformity and precision are 

especially to be desired. The special amount of the Avoirdupois 

ounce is usually indicated by a sign different from that employed 

in the Apothecaries' system: Thus one oz. stands for 437-5 grains; 

while 3j means 480 grains. 

Table of British Pharmacopoeia Avoirdupois Weight 

437.5 grains = one ounce (1 oz.). 
7000 grains = 16 oz. — one pound com. (1 lb.). 

The Measures oj Capacity employed in the U. S. Pharmacopoeia 
are derived either from the wine gallon or from the metric system. 

Table of Wine Measure (U. S. P.) 

1 minim = TTLJ = °-95 grains of water. 

60 minims = 1ft[lx = f^j (fluidram) = 55.9 " 

480 minims = feviij = f^j (fluidounce) = 455-7 " " 

7680 minims = f|xvj = Oj (octarius or pint) = 7291.2 " " 

61440 minims = Oviij = cong. (congius or gallon) = 58328.8 " " 



20 INTRODUCTION 

Originally it was intended that one minim of the standard 
fluid, water, should weigh one grain. In fact, as stated in the 
table, under ordinary conditions it weighs 0.95 grains, while the 
fluidounce weighs only 455.7 grains. There is a much wider 
discrepancy between the pint of 16 fluidounces and the pound of 
12 Troy ounces. In order to make terms of weight and measure 
more easily convertible the British Pharmacopoeia uses a system 
in which the fluidounce of water weighs an Avoirdupois ounce of 
437.5 grains. This system is given below: 

Table of Imperial Measure (B. P.) 



1 minim = min. j 


= 


0.91 


grains of water. 


60 minims = fl. dr. j = tl\lx 


= 


54-68 


it a 


480 minims = fl. oz. j = f^viij 


= 


437-50 


<< «« 


9600 minims = Oj — f^xx 


= 


.8750.00 


tt a 


76800 minims = cong. j = Oviij 


= 


70000.00 


tt tt 



A pint of water is not a pound in the Apothecaries' system, for 

the Troy pound has 12 ounces, while a Wine Measure pint has 16 

ounces. But the Avoirdupois or commercial pound is 16 ounces, 

which is nearer the weight of a pint of water, though not exactly 

equivalent. The pint of water weighs 7291.2 grains, though the 

pound weight itself is equal to only 7000 standard grains. 

Approximate Measures 

A wineglassful is equivalent to about 2 fluidounces. 
A tablespoonful " " ^ fluidounce. 

A dessertspoonful " " 2 fluidrams. 

A teaspoonful " " 1 fluidram. 

The metric system has the great advantages of a common unit 
for measures of weight, capacity, length, and surface, thus per- 
mitting easy conversion of one into terms of another. 

Not only is measuring more easily done than weighing; it is 
also, as a rule, more accurately done. The facility in calculation 
afforded by the metric system is especially seen in the conversions 
of volumetric analysis which enable the analyst, by careful meas- 
urement, to dispense with the weighing of precipitates. All the 
benefits that accrue to arithmetic computations by a decimal 
system of counting (now universal) is shared by our American 
division of coins, and will be further extended wherever the metric 
system of weights and measures is adopted. The natural conser- 
vatism of the English race has delayed its general adoption in 
commerce, in medicine, and in pharmacy, but in chemical and 
physical calculations it is now almost universally employed. 

Metric Units. — The unit of length, called a meter, is the length 
of a standard bar of metal which was supposed to be equal to one 
ten-millionth part of the distance from the equator to the pole. 
The meter is really the length of a certain bar of platinum kept by 
the Department of Weights and Measures in Paris. 



METROLOGY 21 

The unit of capacity, called a liter, is the cube of a tenth part 
of a meter. 

The unit of weight, called a gram, is the weight of so much 
distilled water at its maximum density (4 C.) as will fill a cube 
of the one-hundredth part of a meter. In taking this cubic centi- 
meter of water as a unit of weight a simple and very desirable 
relationship is established between weights and measures. 

The unit of surface, called the are, is the square of ten meters. 

Decimal Table 

In giving names to the decimal multiples a Greek numeral is prefixed ; while 
those of the subdivisions are formed from Latin words signifying the decimal fractions. 

Length. Weight. Capacity. 

1000 = kilometer kilogram kiloliter. 

100 = hectometer hectogram hectoliter. 

10 = decameter decagram decaliter. 

I = Jfeter Gram Liter. 

.1 = decimeter decigram deciliter. 

.01 = centimeter centigram ..... centiliter. 

.001 = millimeter ..... milligram milliliter. 

As a rule, the terms used are the kilometer, kilogram, kiloliter, the 

meter, gram, liter, and the millimeter, milligram, cubic centimeter, or 

milliliter. 

Measures of Length 

1 meter =10 decimeters =100 centimeters = 1000 millimeters. 
1 meter = 1.09363 yards = 3.2809 feet = 39.3709 inches. 

Measures of Capacity 

1 cubic meter = 1000 liters = 1,000,000 cubic centimeters = 1,000,000,000 
cubic millimeters. 

I liter = 61.02705 cubic inches = .035317 cubic foot = 2.1134 pints = .22097 
gallon. 

Measures of Weight 

1 gram = weight of 1 c.c. of water at 4 C. 

I kilogram = 1000 grams = 100,000 centigrams = 1,000,000 milligrams. 

I kilogram = 2.20462 pounds = 35.2739 ounces = 15432.35 grains. 



olids. 








Exact equivalent. 


gram 






=z 


0.006479 gram. 


«< 






= 


0.008098 " 


<« 






= 


0.010798 " 


<« 






= 


O.016200 " 


«< 






= 


0.021599 " 


" 






= 


0.032399 " 


<( 






= 


0.064798 " 


grains 






— 


0.3230 « 
0.6460 " 


scrupl 


e (20 grs.) 




= 


1.2960 " 


dram 


Troy (60 grs.) 




= 


3.888 


ounce 


Troy ( 480 grs. ) 




= 


31.103 •• 


ounce 


Avoirdupois (437.5 


grs-) 


= 


28.350 



2 2 INTRODUCTION 

Measures of Weight 

Liquids. Exact equivalent. 

I minim = 0.06 1 cubic centimeter. 

1 fluidram = 3.697 cubic centimeters. 

1 fluidounce = 29.574 " " 

4 fluidounces (i liter) = 118.295 " " 

8 « (i » ) = 236.590 « 

I pint (Miter) = 473.180 " " 

1 quart = .946 liter. 

To facilitate mental translations from the decimal system to 
the one used in this country, and for rapid reference, the follow- 
ing approximate equivalents are recommended as easy to mem- 
orize: 

Approximate Equivalents 

I meter = 3 feet, 3§ inches. 

I kilometer = f mile. 

I millimeter = 2V mc ^ 

I liter = 2. 113 pints (U. S.), or about I quart. 

I kilogram = 2\ pounds, Avoirdupois. 

I gram = 15^ grains, or about -J^ ounce. 

I milligram = ^5 grain. 

I are = a square, the side of which is 1 1 yards. 

On the basis of calculating 65 milligrams to make a grain and 
32 grams to the ounce, Troy, the following round numbers may 
be of service in prescription writing, being sufficiently accurate for 
that purpose: 

ITU or grain j = I 06 gram or cubic centimeter. 

f£j or sjj = 4 grams or cubic centimeters. 

f §J or Ij = 32 I 

The line is used instead of a decimal point, the figures standing 
for solid grams or fluid cubic centimeters. A teaspoon holds 
about 5 c.c. and a tablespoon about 20 c.c. 

The United States nickel (five-cent piece) weighs 5 grams, and 
is 2 centimeters in diameter. 

Specific Gravity. — If we take equal volumes of different 
substances we find that there are great variations in the weights. 
If a certain volume of hydrogen, the lightest element, weighs 
1 grain, the same volume of air weighs 14; of water, 11,943; and 
of osmium, the heaviest element, 267,553. There is a constant 
and peculiar relationship between the weight and the volume 
of every natural substance. This relationship is called the specific 
gravity. The specific gravity of a body is its weight, as compared 
with the weight of an equal bulk of a standard body taken as 
unity. 

The density of that body is its mass or quantity, as compared 
with the mass of an equal volume of a standard substance. By 
the law of gravitation the weight or gravitative force is directly 



METROLOGY 



23 



proportionate to the mass, hence no error ordinarily results from 
the indifferent employment of the two terms. Sometimes the 
term density is used to signify the specific gravity of a vapor, 
taking hydrogen as a unit. 

Water is so easily obtained in a pure state that it is chosen as 
a standard for both liquids and solids; that is, the latter are said 
to be so much lighter or so much heavier than water. When it 
is said that the specific gravity of urine is 1020, it is meant that a 
bulk of urine equal to the bulk of 1.0 part of water will weigh 
1.020 parts. Likewise we say that the specific gravity of a dry 
gall-stone is 0.9, meaning that equal bulks of water and the con- 
cretion bear the proportion to each other by weight of 1 and 0.9. 

For specific gravity of solids heavier than water application 
is made of the principle that a substance immersed in a liquid 
displaces a bulk of that liquid equal to the bulk of the body im- 
mersed. 

The body may be slowly submerged in the water contained in 
a suitable vessel filled to the brim. The overflow is caught and 
weighed, and the ratio calculated as follows: 

Weight of water : weight of body : : 1 : specific gravity. 

Thus, a piece of sulphur weighing 32 grams and held by a 
thread was very slowly immersed in a lipped vessel filled to the 
brim with water. The overflow was caught in a tared beaker, and 
weighed 16.5 grams. Then — 

16.5 : 32 :: 1 : specific gravity = 1.9 + • 

A more convenient and accurate method makes use of the law: 
"A solid immersed in a liquid loses a weight equal to the weight 
of an equal volume of the liquid." The body is suspended by 
a fine thread or platinum wire, and weighed in the air. It is 
next totally immersed in pure water and its weight noted. By 
subtracting the weight in water from the weight in air we obtain 
the loss in weight, which represents the weight of an equal bulk 
of water. Then — 

Loss in water : weight in air : : 1 : specific gravity. 

For example, weight of body in air, 9.560 grams, 
weight in water, 8.540 " 
loss in weight, 1.02 " 

Therefore, 1.02 : 9.56 : : 1 : specific gravity = 9.37. 



24 INTRODUCTION 

By Rule. — Divide the weight in air by the loss oj weight in 
water, and the quotient is the specific gravity, with water as the 
unit. 

For solids lighter than water and which float of themselves it 
is necessary to add a sinker, such as a glass bead full of mercury, 
or a piece of lead. The body is weighed and then attached to a 
sinker which has been previously weighed in air and in water, and 
its loss noted. The two are weighed together, first in air and then 
in water, to determine their joint loss. The joint loss, less the 
loss of sinker, gives the loss of the light body. 

From this the specific gravity is determined, as above, by divid- 
ing the weight of the light body in air by the loss of weight in 
water. For example: a dry biliary concretion floats on water; if 
it be sunk by attaching to it the heavy body used in the illustra- 
tion of finding the specific gravity of solids heavier than water, 
then — 

Concretion weighs in air, 0.910 grams, 

sinker weighs in air, 9-5^ " 

both weigh in air, 10.47 

both weigh in water, 8.47 



both lose in water, 2.00 

sinker loses in water, 1.02 

then concretion loses in water, 0.08 



and 0.910-^0.98 = 0.928 = specific gravity of concretion. 

For Powders. — After noting the weight of the powder (w) put 
it in a counterpoised bottle with a mark of capacity, say 50 c.c. or 
grams. Fill the bottle to the mark with pure water and weigh. 
From the joint weight subtract the weight of the powder; this 
will give the weight of the water, which, subtracted from the 
known weight of the water filling the bottle 50 grams, will leave 
the weight of a volume of water equal to that of the powder (w r ). 
From these factors the specific gravity is calculated by the same 
rule-of-three as in previous cases: 

Weight of water (w') : weight of body (w) : : 1 : specific gravity. 

For Liquids. — In the metric system the weight of 1 c.c. of 
water at 4 C. (39.2 ° F.) is called 1 gram, therefore, the weight 
in grams of 1 c.c. of a liquid is identical with its specific gravity. 

When the sample to be tested is small in amount, a rapid com- 
putation can be made by weighing, in grams, the liquid in a glass 
pipet holding 1 c.c. when filled to the mark (Fig. 1). The liquid 
is drawn up above the scratched ring on the neck by suction with 



METROLOGY 



25 



the mouth or with a rubber medicine-dropper. The excess is per- 
mitted to drop out until the level of the ring is reached. Then, 
having detached the rubber tube and wiped the glass dry, the 
pipet and contents are weighed in a horizontal position on a wire 




Fig. i. — Specific gravity pipet. 



rack or on the scale-pan. A counterpoise or tare should be made 
in advance, to cancel the weight of the empty pipet and rack. As 
stated above, the weight of the liquid will be its specific gravity. 
The process is convenient and the liability of error is less than 
0.00 1. When larger quantities are dealt with the result is even 
more accurate. 

The weight of a liter (1000 c.c.) in kilograms (1000 grams), or the 
weight of 50 c.c. in grams multiplied by 20 (= 1000 c.c. in kilograms) 
is the specific gravity of the liquid. To take the specific gravity by 

this method a pyknometer (Fig. 2) or 
specific-gravity bottle is used. This 
bottle has a narrow neck and may be 
obtained small enough to contain 5 or 
50 c.c, or perhaps fully 1000 grains of 
water, or, in fact, any known quantity 
capable of being weighed on a delicate 





Fig. 



-Pyknometer: a, Thermometer 
in neck of bottle. 



Fig. 3. — Hydrometer. 



balance. An accurate tare for the empty bottle is placed in the 
opposite scale-pan. The bottle is filled to the mark or perhaps to 



26 INTRODUCTION 

the brim with the liquid, and wiped dry on the outside. It is then 
carefully weighed. If it be a iooo-grain bottle the weight in 
grains will at once stand for specific gravity with water as iooo. 
A rule-of-three sum will be needed if the capacity is other than 
iooo, as — 

Known capacity : weight of liquid : : i : specific gravity. 

In careful observations it is necessary to make allowance 
for variations of temperature, which by expanding or contracting 
the fluid will alter its specific relationship to an equal bulk of 
water at 15.5 ° C. (6o° F.), the standard point. By the use of ice 
in a surrounding vessel the temperature of the fluid can be held 
at 15.5 ° C. (6o° F.) while under examination. With simple 
liquids calculation with a factor of error for variation may be used. 
For the urine a rough allowance is made of 1 degree of specific 
gravity on the hydrometer scale for each 3 ° C. (5. 4 F.) of tempera- 
ture above or below the temperature at which the hydrometer 
or urinometer was standardized. Thus the specific gravity of a 
sample of urine was 1025 when the room temperature was 21.5 C. 
(71 F.) as 21.5 ° is 6° higher than the standard, we must add 
2 degrees of specific gravity to the 1025, making 1027. If the room 
temperature was lower than 15.5 ° C. the difference must be sub- 
tracted according to the same allowance. On the continent of 
Europe the point of maximum density of water, 4 C. (39.2 °), is 
chosen for comparison. The tables of the U. S. Pharmacopoeia 
are based upon a standard temperature of 25 ° C. (77 F.) which 
was adopted because the average temperature of laboratories 
in the United States is 77 ° F. 

Hydrometer. — Though not quite so accurate in its results as 
the method by the pyknometer, that by the hydrometer (Fig. 3) 
has the commendations of being very easy and ready, and of dis- 
pensing with weights and balance. It is therefore commonly 
resorted to in medicine, pharmacy, and the other arts. The 
hydrometer is a spindle-shaped glass instrument, having a grad- 
uated stem above and a weighted bulb below, intended to float 
upright and measure the volume of liquid displaced. The zero of 
the graduated scale is the point (a) to which the instrument sinks 
in pure water, and may stand for iooo or for 1.000. Degrees 
above and below this point indicate the specific gravity of the 
liquid, the surface level of which makes a line coinciding with the 
mark (b) on the upright scale of the floating instrument. Special 
scales are made for use in the arts by which the strength of aqueous 
solutions, or the percentage of alcohol in various spirits may be 
expeditiously determined. These, according to their purpose, 



METROLOGY 27 

are styled lactometer, urinometer, saccharometer, alcoholometer, 
etc. 

Physicians frequently use the urinometer to determine the 
amount of ''solid urine" dissolved, and also to get a clue as to the 
presence of albumin or sugar. Its various applications are dis- 
cussed on pages 569, 583. The scale of the urinometer is marked 
for liquids heavier than water, and usually ranges from zero or 
1000 at the top to 60, meaning 1060, at the bottom. In practising 
this method the glass cylindric vessel which usually accompanies 
it should be about two-thirds full of urine and the urinometer 
gently immersed to about 1020 and then allowed to come to a 
stand. If the vessel has a perfectly flat rim, it may be slowly 
filled to the brim with urine and then the reading made with the 
eye on a level. In this way the most trustworthy register can be 
taken. 

For gases the specific gravity is determined in the same man- 
ner as for liquids by the pyknometer. A glass vessel of known 
air capacity is exhausted by the air-pump, counterpoised, filled 
with the gas, and weighed. Air is taken as a standard, and the 
calculation for comparing the weights of equal volumes of air and 
gas is on the same principle as that given for liquids. 

For vapor density a series of very delicate operations is required, 
which, while they have no medical interest, yet are of great im- 
portance in determining molecular weights. Vapors are gases 
that condense to liquids or solids at ordinary temperatures. Ac- 
cording to the method of Dumas a small glass flask, with a capillary 
opening in its narrow neck, is first weighed full of air. The 
flask is then warmed and its neck dipped into a fluid, some of 
which enters as the contained air cools and contracts. 

In a bath of oil or mercury heated above the boiling-point the 
substance vaporizes, displacing the air. The neck is sealed with 
the blowpipe and when cool weighed. In order to find the 
weight of the empty vessel the point is broken with the neck under 
mercury. The mercury rushes in, replacing the vapor, and 
filling the flask. By measuring this mercury the capacity of the 
flask is ascertained. Then the weight of this much air at the same 
temperature and barometric pressure, subtracted from the original 
weight of the vessel full of air, gives the weight of the empty flask. 
This weight, subtracted from the weight of the flask full of vapor, 
gives the weight of the known volume of the vapor at the tem- 
perature and atmospheric pressure at which the flask was sealed. 
Then — Weight of air : weight of vapor : : 1 : vapor density. 



28 HEAT 



HEAT 



THERMOMETRY 

The temperature of substances involved in chemical reactions 
is almost as important as their weight, for the chemical properties 
and behavior of bodies vary greatly with their temperature. In 
clinical observation of disease the temperature of the patient should 
never be overlooked. The presence or absence of fever is always 
noted most accurately by the temperature. Indeed, it has been 
said that the study of fever is mainly a study of temperature. The 
sensation of heat or cold imparted to the hand is an unsafe guide. 
It depends upon the state of the hand, and this varies greatly in 
different persons and at different times in the same person. The 
hand may have been chilled by recent immersion in cold water 
or exposure to cold air, or by temporary sluggishness of the cir- 
culation of the blood. On the contrary, it may be warmer than 
usual by recent immersion in warm water, or by the protection of 
gloves, or by exposure to the air of a warm room. 

A hot body, besides communicating to the observer the sensa- 
tion of heat, which is relative, imparts to other bodies in contact 
or near relation to it an increase in size which is constant. In 
general, as bodies get hotter they expand; as they cool, they con- 
tract. This physical change is objective, constant, and inde- 
pendent of the condition of the observer. By resort to ther- 
mometers measuring the degree of expansion we get the standard 
desired. 

The degree of expansion determines the state of aggregation; 
that is, whether it be a solid, a liquid, or a vapor. Water below 
o° C. (32 F.) is solid (ice); between o° C. (32 F.) and ioo° C. 
(212 F.) it is liquid; and above ioo° C. (212 F.) it is a vapor 
(steam). By cold and pressure all gases have been liquefied and 
solidified. 

The molecular theory ascribes this threefold state to varia- 
tions in the range and energy of motion of the extremely minute 
particles of which all bodies are composed. These particles, called 
molecules (little masses), are supposed to be always in vibration. 
Their diameter has been calculated to be between -^-Jo" millionth 
and -g-J-Q millionth of an inch. In a solid body, though still in 
agitation, they are supposed to be held in a certain definite relation 
to one another by the operation of an attractive force called 
cohesion. 

Cohesion is commonly defined as an attraction between mole- 
cules exerted at extremely small distances and manifested most 
strongly in solids, less in liquids, and not at all in gases. In 



THERMOMETRY 20. 

solids this resistance to separating forces is very great and its 
phases are distinguished as hardness, brittleness, malleability, 
ductility, and tenacity. The effect of heat is to antagonize cohesion, 
giving a wider sweep to the motion of the molecules, thus causing 
expansion. This phenomenon may be shown with a brass ball 
having a close-fitting ring gauge. When heated by a lamp it 
is found too large for the gauge, but plunged in cold water it con- 
tracts and slips through the ring easily. 

In the liquid state the molecules are more free to move, though 
still somewhat under the sway of cohesion. A small mass of 
liquid mercury rounds up into a globule by virtue of this phe- 
nomenon of cohesion. This same property of holding together 
enables one to blow a soap-bubble to a thin film. The greater 
freedom of the molecules in a liquid permits "them to separate 
further than they do in a solid by equal increments of heat. The 
amount of expansion in a solid is relatively small for the ordinary 
range of temperature. 

When heated from the freezing-point to the boiling-point of 
water, iron expands only 2x2 °^ * ts DU lk; brass only p^-; but 
alcohol increases ^-, water -%-$, and mercury -^. 

The kinetic theory supposes a simple gas to consist of 
molecules all alike in weight, shape, and structure. Although 
smaller than can be discerned with the microscope, they have 
been theoretically counted by the physicist and mathematician, 
and their rate of motion determined. There are many millions 
in a cubic inch of air or other vapor, moving freely in all directions 
with the greatest swiftness. 

In the air at 15.5 ° C. (6o° F.) the average speed is 1570 feet a 
second. The temperature depends on, and is another expression 
for the kinetic energy, or the rate at which the molecules are 
moving. Millions of times in each second each one of these 
molecules happens by chance to strike one of its neighbors, and 
the two rebound like rubber balls, behaving as though they were 
elastic. 

"If we could see them we should be reminded of the dance 
of a swarm of house-flies in the summer air, darting about, touch- 
ing one another, and then sharply darting away in a new direction. 
This agitation is independent of winds or any current. In calm 
air, though all are in motion, as many go in any one direction as 
in any other, and the effect is evenly balanced. In a wind more 
molecules move in the direction of the wind than in any other. 
The molecules are not aimed at one another, and as a collision is 
all a matter of chance the same molecule is sometimes nearly 
stopped, sometimes hurried, and sometimes merely deflected. The 
great majority, however, move with about the average speed of 



3° 



HEAT 



the whole crowd. Gas is a word for a crowd of free molecules, 
as nation is a word for a crowd of men." 

According to this theory the pressure of a gas or vapor is the 
cannonade of millions of molecules against the side of the vessel 
containing the gas. As the number of impacts per square inch 
and per second is enormous, the effect is indistinguishable from 
that of continuous pressure. 

There comes a point in the expansion of a liquid when its mole- 
cules are given such a swing as to pass out of the limited range 
of liquid cohesion into the free state of vapor. As stated above, 
they are supposed now to be in rapid and incessant motion, shoot- 
ing about in straight paths against one another and creating a cer- 
tain pressure on the walls of the containing vessel. This is known 
as vapor tension. Gases expand relatively far more than do 
solids or liquids by equal increments of heat. The molecular 
activities of all gases are so much alike that they expand with 
little or no differences among themselves. Certainly in ordinary 
observation the rate of expansion of air, of hydrogen, of nitrogen, 
of carbon dioxid, and of most other gases, is about the same 
(Charles' or Gay-Lussac's law), being 27-3- P art °f their volume 
ato° C. (3 2 F.) for every increase of i° C. (4^ for i° F.). 1 The 
total expansion in being heated through the ioo° C. (180 F.) 
from o° C. (3 2 F.) is more than one-third their bulk. For this 
reason thermoscopes, which measure the variations in bulk of vapors, 
are extremely sensitive and are often used for precise observations of 
minor changes within a short range. Any substance which 
expands uniformly, and whose alterations of volume under heat can 
be measured, will serve for a thermometer. Mercury has advan- 
tages which commend it to universal use. It can easily be pro- 
cured of standard purity; it expands uniformly and with a rela- 
tively high rate for a liquid; it has the conductivity of a metal, 
readily settling by loss or gain to the temperature of contiguous 
bodies. It has a range of 389 ° C. (700 F.) between its freezing- 
and its boiling-point. Temperatures below - 39. 4 C. ( — 38.9° 
F.), the freezing-point of mercury, are taken with colored alcohol. 
Above 350 C. (662 ° F.), where mercury boils, the air pyrometer 
is used. 

1 Correction of Volume for Temperature. — The decimal corresponding to 27-3 is 
0.003665, which is called the co-efficient of expansion of gases. When heated from 
o° C. (32 F. ) to i° C. (33. 8° F.) one volume of air or of nitrogen becomes 
1.003665 volumes; at 2 C. (35. 6° F.) it would be increased by double the co-efficient 
(0.003665 x 2 ) =0.00733. If the temperature be above o° C. (32 F.), in order 
to correct the observation by reduction to the standard o°, the observed volume is 
divided by the factor [1 -|- (0.003665 X observed temperature)]. Thus, the volume 
of nitrogen in an urea apparatus was 60 c.c, the temperature of the room was 20 C. 
(68° F.), what would be the volume at o° C. (32 F.) ? Answer: 1 +(0.003665 
X2o°)=i. 07330. Then 60-^1.0733-- 55. 90 c - c - 



THERMOMETRY 



31 



c 

IOO° 

90 

So _ 

70 _ 

6O — 

- 

SO _ 

40 _ 

JO _ 



'O 



-20 -A 



F. 



R. 
80' 



191 _72 



/76 _ tf * 



/5* _ 56 



//<? _ 48 



—/2Z — 40 



— /o4 _3l 



— 86 _Z4 



68 



— SO 



/6 



J* 



The Mercurial Thermometer.— A thermometer of precis- 
ion ought to be made of a selected tube which is carefully divided 
into parts of equal volume of the bore (Fig. 4). Two fixed 
points are marked as standard: 
the point reached by the mer- 
cury when the instrument is 
embedded in melting ice, the 
freezing-point and another 
point higher up reached when 
exposed to steam at average 
atmospheric pressure, the boil- 
ing-point. The freezing-point 
on the Centigrade scale is 
marked zero (o°); between it 
and the boiling-point one hun- 
dred degrees are marked. On 
Fahrenheit's scale the freezing- 
point is called 32 ° and the boil- 
ing-point 212 , there being 180 
between them. In Reaumur's 
scale the freezing-point is 
marked o°, but the boiling- 
point is 8o°. In English-speak- 
ing countries both Centigrade 
and Fahrenheit are used, the 
latter almost exclusively by phys- 
icians, by the weather bureau, 
and in the household. In 
chemical circles in this country 
and in most countries of Europe the Centigrade is preferred. 
In making the scales the space covered by 100 ° C. includes 180 ° 
F., hence their relative values are as 1 to 1.8 or as 5 to 9. This 
relation is complicated by the fact that Fahrenheit's zero is not at 
the freezing-point, but at thirty-two of his degrees below it. To 
start from the same point for both we must add or subtract 32, 
according to circumstances. Briefly then: 

To convert Centigrade above o° to Fahrenheit, multiply by 9 
and divide by 5 and add 32 to the product. To illustrate: The 
point when water is densest is 4 C; what is this according to 
Fahrenheit? 

4 °X9 = 36°, 3 6°-5 = 7-2°, 7-2 + 3 2 = 39-2° F - 

The formula for this calculation is F. = -| C. + 32. 

To convert Fahrenheit into Centigrade degrees subtract 32, 
multiply the remainder by 5, and divide by 9. To illustrate: The 



O 



/* —6 



UT4 — te- 



Fig. 4. — Thermometer showing Centigrade, 
Fahrenheit, and Reaumur scales. 



32 HEAT 

normal temperature of the human body is 98.6 ° F., what is this 
on the Centigrade scale? 



q8.6 - 3 2 =:66.6 , 66.6°X5 = 333°, 333°-9 = 37 



The formula for the above is C. = -§■ (F. — 32). 

For degrees below zero a similar calculation is used. Thus, 
mercury freezes at— 39.4 C, what is this reduced to Fahrenheit? 

-39-4°Xf=-7o.9°; and - 7 o. 9 ° + 32°= -38.9° F. 

The Absolute Zero. — As gases shrink -2^3- of their volume 
for each degree of Centigrade (4-g-y f° r l0 F.), it is supposed that 
at — 2 73 C. ( — 459.4° F.) there would be no possibility of further 
shrinkage from loss of heat, and the molecules would be at abso- 
lute rest. This is supposed to be the temperature of interstellar 
space, and is called the absolute zero. Low temperatures are pro- 
duced artificially; —258° C. ( — 432.4° F.) has been obtained by 
allowing liquid hydrogen to boil under diminished pressure. At 
this point, which is 15° C. (27° F.) above absolute zero, the liquid 
hydrogen froze. There is but one gas having a lower boiling- 
and freezing-point than hydrogen, and that is helium, which 
freezes at -268° C. (-450.4° F.) or 5° C. (9° F.) above the 
absolute zero. 

At very low temperatures mercury, alcohol, and even air are 
frozen; hence their expansion cannot be used to measure varia- 
tions of the lowest temperatures. The thermometer often used is 
a platinum wire in an electric circuit with a galvanometer. As 
the temperature falls, the resistance of the platinum falls also, and 
the galvanometer shows a corresponding increase of current- 
strength. Within 30° C. of absolute zero this method is not 
correct. For these lowest points a thermopile is used, of silver 
and platinum, with liquid oxygen as a standard, and a delicate 
galvanometer to detect the difference. It is believed to be accurate 
down to the. melting-point of helium, which is 5° or 6° C. above 
absolute zero. 

The absolute temperature is reckoned from the absolute zero by 
adding 273 to the Centigrade reading and 459 (491—32) to the 
Fahrenheit. Thus, hydrogen freezes at —258° C; therefore 
— 258° + 273°= 15° C. of absolute temperature. 

The Clinical Thermometer. — The instrument used to note the 
variations of human temperature should not only be correct in its 
indications of one-fourth of a degree, but should act quickly (in 
from 1 to 4 minutes), should hold the register at its highest reach, 
even after removal frOm the mouth, anus, or armpit, and should 






THERMOMETRY 33 

be so constructed as easily to be made aseptic. Correctness is 
obtained by graduating after comparison with a standard instru- 
ment at several nearly related temperatures. Sensitiveness or 
promptness of action is produced by having the smallest possible 
volume of mercury in the bulb and a fine bore in the indicating 
column. To make this hair-like column visible it is sometimes 
flattened into a ribbon and the glass shaped to act as a lens. To 
make an instrument self-registering, various devices have been 
employed by which the top of the column is held stationary while 
the mass of the mercury is free to contract within the bulb. The 
principle in common use is that of constricting the tube at some 
point, so that the impediment will arrest the downward motion of 
the mercury above it and break the column. In the best form 
of thermometer the mercury must pass by an extremely narrow 
channel around the sharp corner of a piece of glass sealed into 
the bore. When warmed the expanding mercury is forced past 
this obstruction, but on cooling, the portion which has been 
driven above remains stationary while the lower portion contracts, 
thus making a gap in the column. This stationary portion indi- 
cates the maximum temperature. 

To set the instrument for taking an observation the top of this 
detached column must be lowered to the point of 35 ° C. (95 ° F.). 
This is done by mechanical means, but jarring and striking the 
instrument sometimes causes it to slip out of the hand, to be 
broken on the floor. Centrifugal force serves us best and is 
brought into play by holding the tube firmly with the bulb end 
downward and swinging it briskly or throwing the hand, forward 
and jerking it back quickly, as in cracking a whip. 

It is necessary for accuracy that the instrument should not be 
graduated until the glass is seasoned. The tube is not always uni- 
form in its caliber. It may be correct at 35 ° C. (95 ° F.), but 
incorrect at 38 C. (100. 4 F,). 

On these accounts it has become customary for dealers to 
furnish certificates of correctness which attest accuracy or give 
the factor of error for several points on the scale. For clinical 
purposes, where it is frequently necessary to make an instrument 
aseptic, the glass tube with the scale engraved upon it is to be 
preferred to any form using metal or any other material. The 
smooth and rounded surface is least likely to harbor infectious 
germs, and it can be easily sterilized by immersion in any anti- 
septic fluid such as formaldehyd, alcohol, or solution of cresol. 

The range of human temperature being limited, the scale of the 

clinical thermometer needs to be but a few inches in length. It 

should register variations of one-fourth of a degree from 33.3° C. 

(92 ° F.) to 43.3 ° C. (no° F.), and have marked upon the glass the 

3 



34 HEAT 

minimum time of exposure required for it to reach the true tem- 
perature. The normal temperature is 37 ° C. (98. 6° F.). A 
rise of more than one degree means that the patient is feverish. 
Long-continued temperature above 40.5 ° C. (105 ° F.) is dan- 
gerous because it induces widespread degenerative changes in 
the body. 

Clinical Temperatures 

Above 1 05. 8° F. or 41 ° C Hyperpyrexia. 

Between 104 and 105 F. or 40 and 40. 5 C. ... High fever. 

" 102 and 103 F. or 38. 8° and 39. 4 C. . . . Moderate fever. 

" 99-5° and 101.5 F. or 37. 5 and 38.6 C. . . . Slight fever. 

Normal 98.6 F. or 37 C Health. 

About 97. 7 F. or 36. 5 C Subnormal. 

Below 97 F. or 36 C Collapse. 

SPECIFIC HEAT 

The thermometer is used to mark the intensity with which 
heat acts, but it is necessary to supplement its reading with other 
observations if we would learn the quantity of heat engaged. An 
elevation of temperature of i° in a given quantity of water re- 
quires that a certain amount of heat should be supplied to the 
water; to raise another equal mass of water through i° requires 
an equal amount of heat. It follows, therefore, that twice the 
amount of water in rising through 1 ° will absorb twice the amount 
of heat as was needed for the single mass. This gives us a unit 
for recording the quantity of heat — "the amount required to 
raise one gram of water one degree Centigrade in temperature." 
It is called the gram-degree unit of heat, or the calorie, and is abbre- 
viated cal. 

For stating large transfers of heat, as in dealing with the fuel value 
of foods, it is desirable to have a large unit. The large Calorie (Cal.) 
is the amount of heat required to raise one kilogram of water one 
degree Centigrade or about 1 pound of water 4 degrees Fahrenheit. It 
is equal to 1000 small calories (cal.). 

Heat Capacity. — To raise the temperature of equal masses 
of different substances, such as copper, mercury, or lead, through 
the same number of degrees, different quantities of heat are 
absorbed. This heat reappears when the bodies return to their 
original temperature. Each body is thus shown to have a differ- 
ent capacity for absorbing heat. The thermal capacity of water 
is the heat that must be supplied to it to raise one gram through 
one degree Centigrade. 

In a suitable instrument known as a calorimeter the capacity 
for heat of any body can be compared with that for water. This 
gives us the specific heat of the body, which is the ratio between its 
heat capacity and that oj water taken as 1. When equal weights 



MELTING AND FREEZING 35 

of mercury and water are exposed to the same heat for the same 
period it is found that while the water rises i° C, the mercury 
will rise 30 ° C. Therefore, the thermal capacity of mercury is 
-^0 or 0.0333 that of water — that is, the specific heat of mercury 
(water=i) is 0.0333. 

A study of heat capacity is of great importance to the chemist, 
as it serves for the calculation of atomic weight. The specific 
heat of solid elements is inversely proportional to the atomic 
weight; hence, for solid elements the product of the two is a 
constant quantity. As stated by Dulong and Petit: "The solid 
elements have the same atomic heat." The constant product 
averages 6.4. It follows, therefore, that knowing the specific heat 
of a solid, we can determine the atomic weight by dividing 6.4 by 
the specific heat. 

MELTING AND FREEZING 

The temperature of a solid rises by the application of heat 
until it reaches the melting- or jusitig-point, when a physical 
change occurs, the body becoming a liquid. This change depends 
upon a play of molecular energy which is definite for any given 
substance at a given temperature. It therefore takes place at a 
fixed point for each substance, and is a constant characteristic 
for every substance which is not altered chemically by the action 
of heat. No means of identifying substances and testing their 
purity is more often used than that of the determination of the 
melting-point. When pure, a substance always melts exactly at 
this point. Should a part of it melt at this degree and the other 
part remain solid up to a higher temperature, thus rendering an 
indefinite report, it is evident that we are dealing with a mixture 
and not the pure substance. 

A sharply accurate melting indicates great purity, for the least 
impurity causes a considerable change in the melting-point. The 
following are the melting-points of a few substances: mercury, 
— 39. 4° C. ( — 39° F.); carbolic acid, 35 C. (95 F.); potassium, 
62. 5 C. (144. 5 F.); benzoic acid, 120 C. (248 F.); salicylic 
acid, 155 C. (311 F.); tin, 227. 8° C. (442 F.). 

Determination of the Melting=point (Fig. 5).— A minute 
quantity of the substance is placed in a short capillary tube (c) 
closed at one end and attached to a thermometer (d) by small 
rubber bands. The thermometer carrying the substance is 
immersed in a beaker (a) containing a liquid having a high boiling- 
point, like concentrated sulphuric acid. Heat is applied gradually 
and the acid constantly stirred with a glass stirrer (b) until the 
solid is seen to liquefy. The thermometer reading is then taken 
as the melting-point (m.-p.) of the solid. Freezing or solidification 



36 



HEAT 



of the liquid occurs at a point practically identical with the melting 
of the same substance in its solid state. 

Latent Heat. — When the amount of the solid is considerable, 
much time is consumed in melting, and the thermometer does 
not rise during the whole period of transition from the solid to the 
liquid states, although much heat is being applied. The heat so 
absorbed and unrecorded by the thermometer is called latent; 
because it appears to be stored up and hidden, to reappear as 
sensible or free heat in equal amount when the liquid freezes. 
Strictly speaking, it is no longer that form of molecular vibration 
recognizable as heat, but is the energy employed in overcoming 

molecular cohesion and in maintaining 
the molecules in their new relative posi- 
tions. 

The amount of heat that disappears 
varies with the material substance and 
its mass. Like the melting-point, it is 
definite and characteristic for each 
individual substance. 

Latent heat of fusion is the number 
of calories (heat units) required to 
change one gram of a substance from 
the solid state to the liquid, the tem- 
perature remaining constant. 

If a kilogram of water at o° C. is 
mixed with an equal weight of water 
at ioo° C. there will be two kilo- 
grams at 50 ° C. If a kilogram of ice 
at o° be mixed with a kilogram of 
water at ioo° C, the melted mixture 
will have a temperature of only 10.4 ° C. 
In this last experiment each gram 
weight of water at 100 ° C. in cooling 
to 10. 4 C. will have given off 100 — 
10.4 = 89.6 calories. In losing this 
89.6 calories it has melted one gram 
of ice and warmed up the resulting 
water 10. 4 C, which equals 10.4 calo- 
ries. Subtracting this from the 89.6 
calories gives us 89.6 — 10.4 = 79.2 calories. In melting one gram 
of ice at o° C. there disappeared or was made latent enough heat 
to raise the temperature of a gram of water 79. 2 ° C. The mole- 
cules have used up this energy in acquiring a freedom of move- 
ment among themselves not previously possible while cohesion 
held them in the fixed position characteristic of solids. To 




Fig. 



-Determination of melting- 
point. 



MELTING AND FREEZING 37 

liquefy water requires 79.2 cal., a higher latent heat of fusion 
than any other liquid. Acetic acid requires 43.7 cal.; benzine, 
29.1 cal. 

Effect of Pressure on the Melting=point.— In most cases 
the change from the solid state to the liquid is attended by expan- 
sion. To this rule there are exceptions, such as ice, bismuth, and 
iron, which contract on fusion. A body that expands in fusing 
has its melting-point raised by pressure. The effect of pressure 
is so slight that a pressure of 156 atmospheres raises the melting- 
point of spermaceti only 3 C. (5.4 F.). 

On the other hand, the bodies that contract in fusing have 
their melting-point lowered by pressure. For instance, with ice, 
pressure makes the change to water more easy. In moulding a 
snowball pressure without heat will melt the ice crystals, because 
the compressed snow has a melting-point lower than o° C. (32 ° 
F.). On removing the pressure the ice grows hard again, uniting 
the crystals. This is the phenomenon termed regelation. The 
fusion-point of water is lowered only 0.0075 ° C. (°- OI 35° F.) for 
each atmosphere of pressure. 

Reactions of the State of Equilibrium. — When we have 
made a mixture of ice and water at o° C. (32 F.), in which they 
exist side by side unchanged, if we put pressure on it the equi- 
librium is disturbed. In order to relieve the pressure the ice melts, 
because liquid water occupies less space than the solid. The 
melting-point of the ice is lowered, but, on the other hand, the 
pressure is reduced. This is an illustration of the law of reaction 
which holds for all states of equilibrium in chemistry and physics: 
When a system in equilibrium under constraint shifts its equi- 
librium, there is a reaction which opposes and partially destroys 
the constraint. From this it is seen that an equilibrium is a more 
or less stable condition which, when disturbed, tends to restore 
itself by reversing the disturbance (p. 82). 

Freezing Mixtures. — Making a solution of a solid causes a 
lowering of temperature. As the melting of a solid consumes 
heat, so does the liquefaction of a solid by a solvent. The heat 
is taken from the mass itself. This is the principle involved in 
the production of artificial cold, which may be sufficient in cer- 
tain cases to produce a lowering in temperature of surrounding 
bodies, and thus act as a freezing mixture. The more rapid the 
process of liquefaction the greater is the degree of cold produced, 
as there is less time for heat to be conducted from without. When 
snow or shaved ice, two parts, is mixed with one part of common 
salt, it quickly liquefies and then dissolves the salt, both changes 
reducing the temperature of neighboring substances from o° C. 
to —22 C. (—7.6° F.). A mixture of 5 parts of potassium 



38 HEAT 

nitrate, 5 of ammonium chlorid, and 19 of water lowers the tem- 
perature from io° C. (50 F.) to -12 C. (10.4 F.). 

Cryoscopy. — The freezing-point of a liquid is lowered by 
dissolving in it any substance, solid, liquid, or gaseous. The salt 
water of the sea remains unfrozen when the rivers flowing into it 
are covered with ice. The reduction of temperature is propor- 
tionate to the amount of dissolved substance. Expressed in 
another way, the lowering of the freezing-point is proportionate 
to the number of molecules dissolved in a given volume (p. 96). 

For medical studies cryoscopy is limited to the determination 
of the freezing-point of organic fluids, such as urine, milk, or 
blood, by means of which information is obtained regarding the 
amount of matter held in solution. It is based on the law oj 
Raoult, that a definite quantity of any substance expressed in 
molecules (i. e., the molecular weight of the substance in grams), 
dissolved in a definite quantity of fluid, lowers the freezing-point 
of the solvent by a constant amount. From this it follows that 
the lowering is dependent upon the number of molecules in solution, 
and not upon their nature, size, or material. After dissolving 
in 1000 c.c. of water the molecular weight of any substance in 
grams, we find that the freezing-point of the water is depressed 
1.87 ° C. (3.35 ° F.). This is the value of its molecular lowering. 
In an aqueous solution the amount of depression in Centigrade 
degrees below the freezing-point of pure water is often expressed 
by the symbol //, delta. The A of normal blood is 0.56; that 
of normal urine varies from 1.2 to 2.3; that of cows' milk is 0.55 
to 0.56, whether Pasteurized or not. If the freezing-point of 
a sample of milk is — 0.52 C. (31.06 F.), then it has been 
manipulated. Making allowance for temporary variations, due to 
excessive consumption of water on the one hand, or of salt food 
on the other, depression in the freezing-point of the blood shows 
failure of the kidneys to remove the effete substances. Serious 
disease of the kidneys may depress it one degree below the normal. 

For exact researches upon cryoscopy the apparatus commonly 
used for determining the melting-point of solids is not sufficiently 
precise. The instrument and elaborate technic of Beckmann is best. 

A special differential thermometer (T), graduated into hun- 
dredths of a degree, is inserted into a stout glass tube (^4) one 
inch in diameter, so that the bulb is J of an inch from the bottom 
of the tube. Both of these are fitted, without touching, into a 
larger tube (D), which acts as an air-jacket. 

These are supported in an upright position by a cover (E), 
placed on a glass jar of two-liters capacity. This jar is filled two- 
thirds with shaved ice, two parts, and salt, one part, which is enough 
to lower the temperature to the desired point, about — 5 C. 



EVAPORATION 



39 



(23 ° F.), taken on an ordinary thermometer. The liquid to be 
examined is poured into (^4) by the side tube (B), and in sufficient 
quantity to cover the bulb of the special thermometer; then (A) 
is placed into the larger tube (D), which serves as a cool chamber. 




Fig. 6. — Cryoscopic apparatus. 

The liquid is stirred by the wire (C). In about ten minutes the 
liquid becomes a thick slush; then the freezing-point is read, as dif- 
ferentiated from that of pure water, which has been before deter- 
mined and recorded. Duplicate determinations may be taken to 
insure accuracy. 

EVAPORATION 

A liquid exposed to the air dries up — that is, passes into the 
state of invisible vapor or gas. This spontaneous evaporation 
occurs slowly at all temperatures, but when the liquid is boiled 
the process is much more rapid. It has been stated before that 
the molecules of a liquid have some freedom of motion. This 
motion is sufficient to carry those that have reached the free sur- 



40 



HEAT 



face, with some velocity, beyond the limit of the liquid into the air. 
No longer under the sway of the cohesive force that held the 
molecules in the liquid state, they now move freely in all directions 
in straight paths, some striking others and rebounding, but all 
tending outward. 

In a confined space the evaporation appears to cease very soon, 
but in reality it continues, the movement being only checked, and 
as many rebound to the liquid as leave its surface. When there 
is an equilibrium between evaporation and condensation the 
air-space is said to be saturated with vapor. 

If a few drops of a liquid are permitted to rise through the 
mercury in a barometer tube, as soon as they reach the surface 
they evaporate and the mercury falls. The vapor exerts a pressure 
inside, which counterbalances some of the outer air-pressure 
that previously held the mercury at 760 mm. (30 in.). This 
pressure is due to the bombardment of the molecules and is 
called tension. More liquid will depress the column still further, 
but eventually some will remain unevaporated on top of the mer- 
cury. For that temperature the pressure has reached its max- 
imum and the space is saturated. At a given temperature different 
vapors depress the column to different amounts. At 20 ° C. 
(68° F.) water vapor depressed the column 17 mm. (0.6 in.); 
alcohol vapor 60 mm. (3.54 in.); and ether 450 mm. (17.7 in.). 

If a barometer tube has its space above the mercury saturated 
with vapor, and we raise the temperature about the tube, it will 
be seen that as the temperature rises the barometer column falls, 
showing increased vapor tension. The saturation pressure rises 
correspondingly to the rise of heat. The difference of height 
between an ordinary barometer and one having saturated vapor 
in its upper space gives the vapor tension of water for that tem- 
perature. The saturation vapor-pressures of water are stated in 
the table below: 



Tension of Aqueous Vapor in Millimeters (Reg 


nault) 




Temperature. 


Tension. 


Temperature. 


Tension. 


Temperature. 


Tension. 




C. 


mm. 


C. 


mm. 


C. 


mm. 




o° 


4.6 


11° 


9.8 


21° 


18.5 




1 


4.9 


12 


IO.4 


22 


197 




2 


5-3 


13 


II. I 


23 


20.9 




3 


5-7 


14 


II.9 


24 


22.2 




4 


6.1 


15 


12.7 


25 


23.6 




5 


6-5 


16 


13-5 


26 


25.O 




6 


7.0 


17 


I44 


27 


26.5 




7 


7-5 


18 


15-4 


28 


28.1 




8 


8.0 


19 


16.3 


29 


29.8 




9 


8.5 


20 


17.4 


30 


31.6 




10 


9-i 













BOILING 41 

If the given space be not a vacuum, but already occupied by 
air or other gases at the same temperature, the same quantity of 
aqueous or other vapor will diffuse into it. The only difference 
is that vaporization will go on more slowly because the liquid 
particles encounter resistance to their passage into the space. 
The highest pressure of the new vapor will be the same in the 
occupied space as it was in the vacuum. As each vapor exerts 
its own pressure unaffected by others present, it follows that the 
total pressure of a mixture of vapors would be equal to the sum 
of all the pressures — shown by each separate vapor when con- 
fined singly to the same space. 

BOILING 

If the table of tensions had been extended to 100 ° C. (212 F.), 
it would have stated that the pressure at that point exactly bal- 
anced a column of mercury 760 mm. or 30 in. high — that is, 
it was equal to the weight of the atmosphere. From this we 
deduce the law: that ''boiling of a liquid occurs at the tempera- 
ture which raises the tension of its vapor to a point equal to the 
pressure of the atmosphere." As soon as the tension rises beyond 
that point the liquid molecules are animated with such energy 
that those on the surface line press back the superincumbent 
air and fly with great velocity into the space above the liquid. 
The molecules below the surface form bubbles of vapor which, 
being specifically light, float up to the surface, burst, and scatter 
their contents into the air. 

In consequence of the above law, decreasing the pressure on 
a liquid enables it to boil at a lower temperature. In the vacuum 
of an air-pump water will boil at the temperature of a living room. 
On the other hand, if the pressure be increased, the boiling-point 
rises. In a closed boiler water may be heated far above 100 ° C. 
(212 F.) without boiling, because its vapor is confined and 
presses back upon the liquid, obstructing the free passage of the 
molecules. 

Boiling=point. — A pure liquid under the same conditions 
of pressure always boils at the same temperature. Like the 
melting-point of a solid, the boiling-point of a liquid is so con- 
stant as to be a test for purity. The usual method of determina- 
tion is one which immerses the thermometer in the vapor of the 
boiling liquid just above the surface of the liquid. The liquid 
is put in a flask (A, Fig. 7), having a side tube in the neck (B) 
for the escape of vapor. Through the perforated stopper passes 
a thermometer, which, when boiling begins, is surrounded by the 
vapor. The heat is applied gradually until the liquid boils. As 
soon as the mercury of the thermometer remains constant the 



42 



HEAT 



boiling-point is read off. 
icacy the instrument and 



For observations of extraordinary del- 
technique of Beckmann are used, as 
described on p. 369. 

Very different temperatures are re- 
quired to boil different liquids. While 
water boils at ioo° C. (212 ° F.), mer- 
cury requires 357 ° C. (675 ° F.), abso- 
lute alcohol, 78 C. (173 ° F.), pure 
ether, 35 ° C. (95 ° F.), chloroform, 61 ° 
C. (142 ° F.), oxygen the very low point 
— 180 ° C. ( — 292° F.), and hydrogen 
still lower, -252 C. (-422 F.). 

When a solid is dissolved in a liquid 
the boiling-point rises correspondingly 
with the concentration. Salts dis- 
solved in water prevent its boiling at 
ioo° C. (212 F.). The solid gives 
increased cohesion to the liquid, and 
the greater mutual attraction must be 
overcome by a higher temperature (see 
p. 369). The diminished pressure of 
the atmosphere in high altitudes per- 
mits boiling to occur at a point too 
low for cooking in the boiler. By 
adding kitchen salt the boiling-point 
is raised sufficiently to cook the food, 
the effect of the altitude being can- 
celed by the salt. 
Latent Heat of Vaporization. — The spontaneous conver- 
sion of a liquid into a vapor is accomplished by absorbing heat 
from surrounding objects. They lose heat, hence it is said that 
evaporation is a cooling process. Wet clothes chill the wearer 
because of the evaporation of the water outside. Ether evap- 
orates so rapidly when applied to the skin as to benumb the local 
sensibility through the effect of the cold produced. The absorp- 
tion of heat is required to overcome the cohesion of the liquid 
and to impart to the particles the velocity characteristic of vapors. 
During the whole time of boiling away a liquid its temperature 
never rises above its boiling-point; all the heat not sensible to 
the thermometer is taken up in causing the change of molecular 
condition, and is called the latent heat oj the vapor. The exact 
amount of heat that disappears is evolved again when the vapor 
is condensed. Different liquids require different amounts of heat 
to vaporize them. The latent heat of steam is determined in the 
following manner: 

A kilogram of water at o° C. is heated to ioo° C. by passing 




Fig. 7. — Apparatus for determining 
boiling-point. 



BOILING 43 

steam into it. The water now weighs 1.186 kg. — that is, to raise 
1 kg. ioo° C, 0.186 kg. of steam have been condensed. If 0.186 
kg. of steam will raise 1 kg. of water 100 ° C, then 1 kg. of steam 
will raise 5.37 kg. of water ioo° C. or 537 kg. through i° C. 
Steam then has a latent heat of 537 calories, which is the highest 
of all vapors. 

Supercooled and Superheated Water. — The exact relationship 
stated between the vaporous form and temperature and pressure 
does not obtain unless both the vapor and the liquid are present 
simultaneously. This appears on consideration of the following 
facts: Many substances in the liquid state can be cooled below 
their melting-point without change to the solid state. If air is 
excluded from the containing vessel, water can be lowered in 
temperature 10 degrees below o° C. without freezing, though the 
peculiarity of expanding is retained. If supercooled only a few 
degrees it retains the liquid state indefinitely. At the touch of a 
piece of ready-formed ice it solidifies instantly, the temperature 
of the mass rising to the freezing-point — o° C. (32 F.). In this 
supercooled condition, ready to solidify by contact of ice, water 
is said to be metastable. 

Suspended . Boiling. — In like manner when dissolved gases 
have been removed by previously boiling a liquid it may be heated 
several degrees above its boiling-point without ebullition super- 
vening. After water has been boiled some time in a perfectly 
clean vessel the phenomenon of bumping occurs. The dissolved 
air has been expelled by the first boiling, and the temperature can 
be raised several degrees above ioo° C. (212 F.) without changing 
the state of the water, until at last one bubble of vapor disturbs 
the inertia, and a large evolution of vapor begins with sudden 
explosions. The water heated above its boiling-point is said 
\o be superheated. This is one of the causes of boiler explosions. 

Supercooled Vapor. — By excluding liquid water, aqueous vapor 
may retain its state even when the temperature is reduced below 
the point of condensation, and the vapor subjected to pressure 
greater than suffices for condensation ordinarily. When a re- 
ceiver containing air and water is exhausted by the air-pump, the 
temperature declines and aqueous vapor is condensed like a fog. 
The same experiment performed after twenty-four hours of stand- 
ing shows no mist. The particles floating in the air of the receiver 
have settled down and the supercooled vapor finds no points around 
which to condense. 

Equilibrium of Three Phases. — There is some pressure 
or vapor tension caused by evaporation from ice, though it is but 
little; that from water is greater, that of water vapor greatest of 
the three forms. If accurate observations of these tensions be 
recorded by measured lines — upright ones for pressure and hori- 



44 



HEAT 



zontal ones for temperature — then curves drawn through the meet- 
ing points give the diagram (Fig. 8) for a system in which the three 
phases — ice, water, and vapor — exist side by side. Chemical as 
well as physical reactions are not completed in any one direction, 
as might be inferred from the usual chemical equation, but if the 
products are confined, having reached a certain point short of 
completion, the products stand at an equilibrium like that of water. 
There is but one component of the system ice-water-vapor, which 
is the chemical substance water. The vapor pressure and tempera- 
ture-curves of water are shown in the diagram (Fig. 8). The upright 
line (p) represents the height of pressure of water-vapor and the 
horizontal line (/) the temperature. 

By experiment we learn that the temperature-pressure condi- 
tions of equilibrium between ice, water, and aqueous vapor can 
be represented in the curves radiating from O. 

These diagrammatic curves (OA, OB, and OC) form the bound- 
aries, of three areas, I, II, III. The component water exists as. 
the phase solid (ice) at any point of pressure and temperature 
included in area I; as liquid in area 77; as vapor in area 777. 
In these different areas there is a stable region for the phase 
common to the two curves bounding it. When supercooled. 

water is in a state of suspended 
solidification, this condition of 
metastable equilibrium is repre- 
sented by the curve OA'. 

The Triple Point.— Experi- 
ment shows that when the pres- 
sure is about 4.6 mm. mercury 
and the temperature about o° C. 
(32 ° F.), the three phases are in 
equilibrium; hence this point is 
called triple point. In the dia- 
gram the curves intersect at this 
point, O, where the three phases 
having the same temperature and 
pressure exist side by side. Any change in pressure or tempera- 
ture causes the disappearance of one phase. Increase the pressure 
and the vapor condenses to water, lower it and the water vaporizes. 
Raise the temperature and the ice liquefies, lower it and the water 
solidifies. In Fig. 8 the three curves run out from O to definite 
points well within the limits of the diagram. Thus, the abrupt 
terminal, A, expresses the well-known fact that there is a critical 
temperature, above which water can no longer exist as liquid. 
This extremity of OA shows also the critical pressure at which the 
two phases, water and vapor, disappear in the one phase — vapor. 



4-6 




Fig. 8. 



-Temperature-pressure diagram of 
water. 



THE GALVANIC CURRENT 



45 



MAGNETISM AND ELECTRICITY 



THE GALVANIC CURRENT 

Lodestone or leadstone is the name applied to a piece of magnetic 
iron oxid, Fe 3 4 , because when suspended it leads or points to 
the poles of the earth. This natural magnet attracts iron, and if 
rubbed on steel bars or needles imparts to them its property of 
pointing north and south. The end that points north is called 
the south pole of the magnet, and that which points south, the 
north pole of the magnet. Such a magnet, dipped into iron 
filings, will carry away at its polar ends a quantity of the filings, 
bristling like a brush. If the north pole of one magnet be brought 
near to the north pole of another that is freely suspended, the 
latter will move away. The south pole, however, will be drawn 
to it. In the same way the south pole repels the south pole, but 
attracts the north. 

The law of magnetic poles is that like poles repel, and unlike 
poles attract. 

The earth is a great magnet, having a field of influence cover- 
ing its entire surface, so that a magnetic compass at any place 
will show by its direction the situation of the poles that attract it. 

The Galvanic Cell. — If plates of two dissimilar substances, 
like copper and zinc, or carbon and zinc, are immersed in an acid 
or other fluid which corrodes 
one of them, at the outside 
ends there will appear manifes- 
tations of energy. If the ends 
of the plates are connected by 
-a wire, a succession of effects 
will be observed as though a 
continuous current of electric 
force was flowing through it. 
For instance: A magnetic needle 
placed near the plates tends to 
take a position at right angles 
to them just as long as they are 
connected by the wire, but no 

longer. If a solution be made a part of the circuit by immersing 
the ends of the wires, then chemical decomposition ensues. Chem- 
ical action upon the zinc plate transmits electricity from that plate 
through the liquid to the other plate which is not corroded, thereby 
generating a state of energy. It is similar to raising the level of 
a reservoir of water connected by a pipe with another one on a 
lower level. This phenomenon is called a difference oj potential 




Fig. g. — Voltaic cell of copper (Cu) and 
zinc {Zn) immersed in sulphuric acid, showing 
direction of the current. 



46 MAGNETISM AND ELECTRICITY 

between the plates which, when the wire outside connects them, 
becomes a current capable of manifesting active energy, just as 
the stream flowing from a higher to a lower level may do many 
kinds of work on the way. 

As the action on the zinc plate originates the current, that 
plate has the higher potential. It is called positive, + ; but the out- 
side end or wire, called its pole, is electrically opposite and is said 
to be negative, — . The other plate (copper, carbon, or other 
substance) of lower potential is negative, — ; and its pole is posi- 
tive, + . 

The power that initiates this transfer of electricity or difference 
of potential is called electromotive force (E. M. F.). As a differ- 
ence of level in a water-system causes a corresponding pressure, 
so a difference of potential causes pressure or voltage in proportion 
to that difference. According to the electronic theory, a body 
excited by negative electricity is considered to have a charge of 
excessively minute electrons detached from the molecules by 
chemical or physical action. A body is positively electrified 
when it has lost electrons, and negatively electrified when it 
has gained them. The gain in electrons at the excited zinc end 
of a battery starts a transfer of them through the cell to the carbon 
end, which is relatively deficient. This movement of electrons 
along the conductor, from one molecule to the next, is something 
like the "handing on" of water by a line of bucket holders from 
the well or pond to a house afire. 

The outer polar wires, being the means for the transmission of 
the current, are called electrodes. The positive pole of the copper 
plate is termed the anode from the greek prefix an-, up, the current 
moving from it up stream; while the negative pole coming from 
the zinc plate bears the name cathode, from the prefix cath-, down, 
the current moving to it down-stream. When the connections 
outside are continuous the circuit is closed; if they are broken, 
it is open. When the current is interrupted intentionally it is said 
to be made and broken. Copper wire is commonly used for con- 
nection because, like all metals, it is- a good conductor. The glass 
of the cell prevents the current passing out by the bottom or 
sides because glass is an insulator or non-conductor, like dry 
wood, vulcanite, mica, and asbestos. Even the best conductors 
offer some resistance to the current, as does a conduit to the stream 
flowing through it. 

To overcome resistance the impelling force must be increased. 
In the cell this is done by choosing two plates of high difference 
of potential. Carbon and zinc, when coupled, have a higher 
relative intensity than copper and zinc, which soon lose what 
little they had at the start. Close examination of the copper 



THE GALVANIC CURRENT 



47 



plate shows that bubbles of hydrogen collect on it, converting 
the surface into one of hydrogen and not of copper. 



Zn 


+ 


H 2 S0 4 


ZnS0 4 


+ H 2 


Zinc. 




Sulphuric acid. 


Zinc sulphate. 


Free hydrogen. 



The difference of potential is lowered, unless the hydrogen is 
removed as fast as it forms. This is accomplished in a different 
way in each of the various cells that have been devised, such as 
Daniell's, Bunsen's, Groves', the silver chlorid, and the dry cells. 
The two cells most frequently used in laboratories and by phys- 
icians are the bichromate and the Leclanche. 

The bichromate (or Grenet) cell is composed of carbon and 
zinc, excited by a fluid made by dissolving 
two ounces of potassium bichromate in a pint 
of hot water, and adding, when cold, two 
drams of mercury bisulphate and three fluid- 
ounces of commercial sulphuric acid. It 
furnishes a great quantity of current in little 
space and can be arranged so that the zincs 
may be plunged into the acid as the electricity 
is required. The carbon is indestructible. 

This solution forms a compound with the 
hydrogen, preventing the coating on the car- 
bon plate which polarizes it. 

The Leclanche cell has several modifica- 
tions, one of which is called the carbon-cyl- 
inder open-circuit battery. In each there is a 
zinc rod coupled with a compressed cylinder 
of carbon and manganese dioxid. The ex- 
citing fluid is ammonium chlorid, which acts 
on the zinc, forming a zinc-ammonium 
chlorid, while the hydrogen is oxidized and 

removed by the manganese dioxid. This battery, though not well 
adapted for continuous work because it polarizes rapidly, is of 
use for short periods intermittently. It quickly regains its strength; 
when left to itself it is rapidly depolarized, and thus maintains its 
intermittent powers for a long time without needing attention. 
The electromotive force from one cell is 1.5 volts only, but it can 
be raised to a higher degree by linking a number of cells in a series 
— the carbon of one connected with the zinc of the next. 

A combination or battery of six cells has six times the E. M. F. 
of one cell, though there is an increase of internal resistance of 
0.7 of an ohm for each cell. 

Dry Cells. — The principle of the Leclanche cell is used in the 
construction of the ordinary dry cell, which has about the same 




Fig. 10. — Grenet cell of 
carbon and zinc in bichro- 
mate fluid. 



48 



MAGNETISM AND ELECTRICITY 



voltage, but an internal resistance of 0.54 of an ohm. Instead 
of a glass cell, one of zinc is used, its internal surface being the 
positive plate; the external surface is varnished. In this cell is a 





Fig. 11. — Disque Leclanche cell. 



Fig. 12. — Carbon-cylinder battery. 



pasty mixture of ammonium chlorid, plaster, and zinc chlorid. In 
the center is the carbon plate surrounded by granulated carbon 
and manganese dioxid, with a porous septum separating them 
from the ammonium chlorid. Just enough water is added barely 




Fig. 13. — Plunge battery of carbon and zinc. 

to moisten the granulated carbon, and the top is then hermetically 
sealed with wax. The plaster hardens and makes a compact, 
almost unbreakable mass, safely portable because there is no 
glass to break nor liquid to spill. 



THE GALVANIC CURRENT 



49 



The units for measurement of electricity are named after 
the most celebrated workers in this field. They are based upon 
the observed analogy of the electric substance to a fluid flowing 
invisibly as a current from a reservoir which 
creates pressure according to its height, through 
conduits which discharge it into various ma- 
chines for doing work like water lead to a 
turbine or mill-wheel. The amount of work 
(Watt) depends on the quantity of electricity 
passing in a second of time (Ampere) and also 
on the pressure driving the current (Volt). 

Ampere : the unit of current-strength pro- 
duced by the difference of potential of a volt 
through the resistance of an ohm. In order 
that a current of one ampere shall liberate 
i.oi gm. of hydrogen it must flow for 96.540 
seconds through the electrolyte. 

Milliampere: the thousandth part of an 
ampere, of which from 1 to 100 or more may 
be administered to a patient for medical purposes. 

Coulomb : the unit of quantity conveyed by the current of an 
ampere in a second. For the evolution of 1.01 gm. of hydrogen 
by electrolysis 96.540 coulombs must pass through the electro- 
lyte. 




Fig. 14. — Dry battery. 




Fig. 15.— Electrolysis of water: Two volumes of hydrogen at the negative pole and one volume of 
oxygen at the positive pole. 

Farad: the unit of electric capacity; the quantity which, with 
the electromotive force of a volt, would flow through the resist- 
ance of an ohm in one second. 

Ohm: the unit of resistance offered to a current of electricity 
by a wire of pure silver or copper one millimeter in diameter and 
4 



50 MAGNETISM AND ELECTRICITY 

48.61 meters long at 18.3 ° C. (65 ° F.). The resistance of the 
Atlantic cable is 700 ohms. 

Volt : the unit of electromotive force. It equals .9268 of the 
force of one Daniell cell, or .5 the power of a Grenet cell, or .75 
the power of a Leclanche cell. 

Watt : the unit of electric power exerted when the current 
has the strength of one ampere and the electromotive force of 
one volt. Equal to -j\q of a horse power. 

It has been stated above that the current flowing through con- 
nected polar wires has magnetic properties. The deviation of a 
magnetic needle caused by it is increased by encircling the needle 
a number of turns of the insulated conducting wire. In the 
milliamper e- meter , or milam- meter, such a needle moves over a 
graduated arc, the degrees indicated corresponding to the current- 
strength. In medical practice from 1 to 100 or more milliam- 
peres are employed, according to the needs of the case. 

To lower the current-strength, the number of cells thrown into 
the circuit is diminished by a switchboard, or the battery remaining 
the same, resisting material is introduced in the length of the 
conductor. A rheostat is an apparauts for varying and controlling 
the current-strength by adjusting the resistance. It may be made 
of coils of iron or German silver wire, or intercalations of carbon 
or water may be used, all of these being poorer conductors than 
the copper wire. 

Besides the magnetic effects, the current has physical powers 
familiar in the electric lights, heaters, and motors. It does not 
fall within the scope of this work to dwell on these, nor on the 
physiologic and curative relations, but reference must be made 
to the chemical effects, which are of great importance to the theory 
and practice of chemistry. 

Chemical Effects of the Current.— The passage of elec- 
tricity through acidulated water is attended by the chemical 
decomposition of the water into its elements, hydrogen and oxy- 
gen. This is electrolysis, and acidulated water is called an electro- 
lyte. If a solution of copper sulphate (CuS0 4 ) be put into the 
electrolytic cell and the current sent through it by platinum elec- 
trodes, the salt is broken up into its ions — copper (Cu) and the 
group (S0 4 ). Metallic copper comes to the negative pole, or 
cathode, just as did the hydrogen of the water; hence the metals 
and hydrogen are known as cations. The group (S0 4 ) engages 
in a second chemical action upon the water of the solution, decom- 
posing the water and setting free the oxygen, which bubbles 
off at the positive pole or anode, and hence is called the anion. 

S0 4 + H 2 = H 2 S0 4 + O 

Water. Acid sulphuric. Oxygen. 



THE GALVANIC CURRENT 



5- 



When a solution of sodium sulphate (Na 2 S0 4 ) is the electrolyte, 
the first separation is into the cation, sodium (Na) and the anion 
(SOJ. The metal sodium at once acts on the water present, 
producing sodium hydroxid and liberating hydrogen, which 
escapes at the cathode — 



Na, + 2 H„0 



2XaOH + H 2 



In this case also there is a secondary decomposition of the 
water by the S0 4 taking the H 2 and freeing the oxygen. 

All acids, bases, and salts which dissolve and make good con- 
ductors are electrolytes and are decomposable. Many salts 
liquefied by fusion, such as the fused chlorids and hydroxids of 
various metals, are split by the current. In all such cases the 
metal, like the hydrogen ion, wanders to the cathode, and the 
other constituent or ion — the non-metal — goes to the anode. 
Below is a list of some of the elements arranged in a U-shape so 
as to show their electric relations. Any element enumerated is 
found to act as electronegative to those following it, and electro- 
positive to those named before. Speaking generally, those be- 
tween hydrogen and the negative end are called electronegative, 
and form anions; those toward the positive end are electropositive, 
and form cations. 



Negative end. 




Positive end. 


Oxygen. 




Potassium. 


Sulphur. 




Sodium. 


Nitrogen. 




Lithium. 


Fluorin. 




Barium. 


Chlorin. 




Strontium. 


Bromin. 




Calcium. 


Iodin. 




Magnesium 


Selenium. 




Aluminum. 


Phosphorus. 




Manganese. 


Arsenic. 




Zinc. 


Chromium. 




Iron. 


Vanadium. 




Nickel. 


Molybdenum. 




Lead. 


Tungsten. 




Tin. 


Boron. 




Bismuth. 


Carbon. 




Copper. 


Antimony. 




Silver. 


Tellurium. 




Mercurv. 


Tantalum. 


Platinum. 


Silicon. 


Gold. 




H} 


'drogen. 





52 MAGNETISM AND ELECTRICITY 

Electrolysis is subject to certain definite laws based upon 
the principle of chemical equivalence among the elements. In 
the electrolysis of copper sulphate mentioned above, or of other 
metallic salts, a given current liberates the metals in weights 
proportionate to their chemical equivalents. 

Hence Faraday's laws: (i) "All the cells in a circuit have in 
them equivalent amounts of chemical action." (2) "In a given 
time the chemical action in a cell is directly proportionate to the 
current-strength." 

The same current acting separately on a chlorid, a bromid, 
and an iodid liberates 35 gm. of chlorin, 80 gm. of bromin, and 
127 gm. of iodin. These figures are recognized in other relations 
as the equivalents (p. 63) of these elements. 

The gram weights of an element set free in one second by a 
current-strength of one ampere is called the electrochemical equiv- 
alent. That of hydrogen being 0.00001038, from law (1) we 
deduce that to calculate the electrochemical equivalent of any 
other element, it is only necessary to multiply 0.00001038 by the 
chemical equivalent of that element. The chemical equivalent 
of an element is obtained by dividing the valency into the atomic 
weight (p. 114). 

Example: The chemical equivalent of copper being 63.2, how 
many grams will be deposited by 1 ampere in 1 second? Answer: 
63.2X0.00001038 = 0.00656 gm. 

From law (2) we deduce that the mass of copper liberated is 
equal to the product obtained by multiplying the current-strength 
by the number of seconds, and then by the chemical equivalent. 

The Ion Theory. — The best explanation of the facts of elec- 
trolysis is afforded by the theory of electrolytic dissociation. It 
assumes that aqueous solutions of salts, strong acids, and bases 
contain some entire molecules of the compounds and some that 
are separated into ions, having charges of electricity. The ions 
with their opposite + and — electricities are attracted to the oppo- 
site — and + poles, and thus the molecule is split into its constituents, 
other entire molecules become ionized to take their place, and 
these in turn are decomposed. The ion theory has many 
phenomena of heat and chemical action to support it (see pp. 
128-132). 

THE INDUCTION COIL 

When the galvanic current passes through a wire (primary), 
it induces another current in a wire (secondary) near to it. If 
the coarse primary wire be insulated and coiled about a core of iron, 
A, Fig. 16, and a much longer and finer wire is wound outside, 
the ends of this secondary will give remarkable displays of electro- 



CATHODE AND RONTGEN RAYS 



53 



motive force far in excess of those obtainable from batteries or 
electric lighting circuits. Nothing is seen so long as the primary 
current is flowing, but when it is broken a vivid spark passes, owing 
to the current induced in the secondary coil by the interruption of 
that in the primary. To secure a stream of sparks a rapid opening 




Fig. 16. — Induction coil. A, Core of iron rods; B, condenser, to get rid of the extra current which 
runs back on the induced current; C, spring of interrupter; b, iron armature; d, set screw carrying 
platinum point; z c, battery. 

and closing is produced in the primary current by an automatic 
interrupter C which is actuated by the electromagnetism of the 
central iron core. The sparks, coming close together, give intense 
effects, apparently continuous, which .are called the faradic, 
induced, or secondary current. 



CATHODE AND RONTGEN RAYS 

Under ordinary conditions an insulated body charged by 
electricity retains its charge owing to the fact that the air at normal 
pressure offers high resistance to leakage. The electricity of high 
potential produced by an influenced electrical machine or an 
induction coil overcomes this resistance and a sudden spark 
discharges the electrified body. By lowering the air pressure 
with a pump the spark changes in appearance to a luminous 
cloud with brilliant bands. 

If the metallic electrodes are fused into a glass bulb which is 
exhausted of air (Crookes' tube) and a powerful electric current 
passes, giving a spark of 6 inches, the negative electrode (cathode) 
is seen as a disc surrounded by a pale glow beyond which is a dark 



54 MAGNETISM AND ELECTRICITY 

space which extends to the other side of the bulb. The glass 
directly opposite the cathode disc glows brilliantly with a phos- 
phorescent light, which ordinarily is green from the soda in the 
glass. Negative electricity streams from the cathode disc in 
straight lines until it impinges upon the glass wall or the disc of 
the anode as a target. These " cathode rays" are considered to 
be a flight of negatively electrified corpuscles (electrons), which 
are the same no matter what the material of the disc from which 
they are driven. They move with a speed nearly equal to that 
of light, and have a mass a thousand times less than that of a 
hydrogen atom. While they do not penetrate the glass wall of 
the bulb, they can pass through a window in it made of aluminium 
foil, which is of lower density, and when outside are known as 
Lenard rays. 

Beside these rays the glass of the bulb transmits a very different 
set of invisible rays which are produced by the impact of the 




Fig. 17. — Thomson's vacuum regulator tube. 

electrons upon the glass wall or the target of the anode. They 
not only pass through the glass and light up the dark screen of 
a fluoroscope covered with barium or calcium tungstate, affect 
photograph plates, and act physiologically on animal tissues and 
organs, but do these things after penetrating enclosures made of 
opaque substances. They are called "#-rays," because their nature 
was at first unknown, and Rontgen rays, after their discoverer. 
They are supposed to be due to irregular pulsations in the ether, 
(not a train of waves) caused by the bombardment of the target 
with the electrons. The rays are absorbed by different materials 
of a given thickness, roughly in proportion to their density. As 
dense bodies like bone or metal absorb more than flesh and leather, 
the rays penetrating a part of the animal body or a leather purse 
and afterward striking a photograph plate or a fluoroscope, make 
a shadow picture (skiagraph) of the bones in the flesh or the 
coins in a purse. 

Cathode rays are also emitted from certain substances without 
the electric discharge, but after exposure to light especially to the 
ultra-violet. The radio-active metals, uranium, thorium, actinium, 



SPECTROSCOPY 



55 



polonium, and radium give off both cathode and Rbntgen rays 
incessantly, without the stimulus of light or electricity (p. 247). 

Another important property of the Rontgen ray is that of 
converting non-conducting air or other gases into conductors of 
electricity. The charge of an electroscope disappears when it is 
brought near any radio-active body, the rapidity of this silent 
discharge being proportional to the radio-activity. The air is 
supposed to be ionized by the contact of the radiating electrons, 
and the ions carry off the electricity. 



LIGHT 



SPECTROSCOPY 



When a round beam of white light, S (Fig. 18), passes through 
a prism, P, it does not pursue a straight course, as a pencil of light, 
to form a white circle at K, but is bent or re jr acted at an angle 
toward the base of the prism. On emerging from the prism it 
is found to be decomposed into different colored lights which 
diverge to form, on the screen H, a brilliant band called the 
spectrum. This dispersion of the component colors is due to the 




Fig. 18. — Dispersion by a prism. 

fact that the several colored lights have unequal wave-lengths. 
The dense medium of the prism retards the short waves more 
than the long ones, and hence the short waves of violet at one 
end are refracted more than the longer ones of red at the other 
end. In the continuous spectrum from the light of candles, lamps, 
or incandescent solids, six principal groups of colors are desig- 
nated: violet, blue, green, yellow, orange, and red. If the artificial 
light have color in it, the spectrum will show that color predomi- 
nating and the others less bright. (PL 4, Fig. 1, a.) 

When the spectrum is obtained from sunlight passing through 



56 



LIGHT 



a slit, it appears as a band of bright colors crossed by a number 
of fine black lines, called Fraunhojer's lines (Fig. 19). These are 
always present in the same relative position. They are con- 
sidered as shadows caused by the absorption of certain rays in 
their passage through media. Dark lines or bands crossing the 
otherwise continuous spectra are obtained by transmission of the 
pencil of light through colored solids, liquids, or gases. Such 
spectra are called absorption spectra. In PL 4, Fig. 1, b, c, d, are 
shown the dark-banded spectra of blood. 






Indigo. Violet. 




Fig. 19. — Fraunhofer's lines: i. Solar spectrum (the colors are indicated above); 2-7, bright-line 
spectra of incandescent gases. 



The light emitted by a glowing gas forms a spectrum of dis- 
connected bright lines and not of continuous colors, as indicated 
in the table of spectra of different metals when heated to form 
incandescent vapors. In Fig. 19 the position of different lines 
can be determined by reference to the scale at the top, and also 
by the Fraunhofer's lines. As the spectra of different substances 
always give different combinations of lines and bands, an impor- 
tant means of identification is afforded by spectrum analysis. 

The spectroscope is an instrument for studying the spectra. 
It consists of a slit at v (Fig. 20), for which there is an adjustable 
shutter to regulate the beam of light emitted by the incandescent 



SPECTROSCOPY 



57 



metal or that transmitted through blood or other colored media. 
In the telescope B there is a lens for collecting the light of the slit 
in parallel rays and throwing it upon the prism P. The telescope 
A serves for the observer to catch the dispersed light after emerg- 
ing from the prism, and telescope C gives the image a standard 
scale in millimeters, illuminated by the candle F and reflected by 
the face of the prism, so that the observer sees it in front of the 
spectrum. By this micrometer scale the relative distances of the 
bands and lines can be noted. 

The direct-vision spectroscope is a single brass tube having an 
adjustable slit, a lens focussing the parallel rays upon a series of 
prisms, two of flint and three of crown glass, arranged in a direct 
line between the lisrrit and the eve. The combination of different 
prisms decomposes the light without deflecting it from the straight 
path. 




Fig. 20. — Spectroscope. 



The spectra in Fig. 19 were exhibited by salts of the metals 
indicated in symbols when heated on the tip of a platinum needle 
in a Bunsen flame. The spectrum at the top shows some of the 
most important of the Fraunhofer dark lines, marked with the 
letters by which they are usually designated. The spectrum of 
sodium (Na) is marked by a brilliant yellow line; potassium (K) 
has two characteristic lines, one red and the other violet; lithium 
(Li) a brilliant red and a fainter orange line. The important lines 
of strontium (Sr) are in the yellow, red, and blue; barium (Ba), 
in the green; rubidium (Rb), in the violet and dark red; cesium 
(Cs), in the blue; and thallium (Tl), in the green. 

Beyond the visible limits of the solar spectrum at both ends 
there are invisible rays recognized by their heating (calorific) and 



58 LIGHT 

their chemical (actinic) effects. Not more than one-fourth of the 
rays of the solar spectrum are visible. At one end the calorific 
rays have longer wave-lengths than the visible red, and hence are 
called infrared rays. At the other end actinic rays are more re- 
frangible and have shorter wave-lengths than the luminous violet, 
and hence are called ultraviolet rays. When a solution of quinin 
sulphate is placed in this dark ultraviolet region, pale-blue rays 
are seen. Substances which, like quinin and kerosene, have the 
property of being colorless by transmitted light and of lighting 
up when observed in reflected light, are said to be fluorescent. 
They lessen the speed of the invisible ultraviolet rays and thus 
lower their refrangibility, bringing them within the limits percept- 
ible to the eye. 

The Ethereal Waves. — The universe is supposed to be per- 
vaded by an elastic medium known as the ether, which can vibrate 
from side to side. The rate of vibrations, according as they 
are fast or slow, causes a variety of effects. While all of them 
travel by impulses from their sources at the same speed as light 
(300,000 kilometers or 186,000 miles a second), their oscillations 
from side to side may be slower than 2 or 3 to the minute and 
faster than one million times a minute. The very slow waves 
are the electric Hertzian waves used in wireless telegraphy; 
much faster are the waves of radiant dull heat; still faster, red 
light; then yellow, and on through the colors of the spectrum to 
violet; at a higher rate are the ultraviolet rays. The x-rays of 
Rbntgen issuing from a Crookes' tube are probably a series of short 
pulses in the ether sent out at irregular intervals. Being irregular 
and unlike a train of waves, they are not lost in the regular vibra- 
tions of surrounding bodies, but are transmitted with little change. 

POLARIMETRY 

Iceland spar and some other crystals possess the peculiar 
property of splitting a transmitted ray of light into two parts. 
An object viewed through such crystals shows two images, one 
being made by the ordinary rays of light corresponding to single 
refraction, and the other by the extra- ordinary, which differs from 
the commonly refracted light. If these extraordinary rays are 
sent through a second similar crystal, and the second crystal be 
rotated, two of the rays disappear and the field of view becomes 
dark; further rotation causes return of brightness. 

The effect of the first crystal has been to alter the light so 
that the second crystal, at right angles, does not transmit the 
modified ray. The light is said to be polarized — that is, made to 
vibrate in one plane. Light commonly vibrates in all planes, 



POLARIMETRY 



59 



though for convenience it may be regarded as in two planes at 
right angles. The eye detects no difference between common 
and polarized light, hence to determine the presence of this prop- 
erty a second crystal must be used, called the analyzer. In Fig. 
21 the set of vertical rods (A) represents the first crystal or polar- 
izer, stopping the rays in a horizontal plane, but allowing the 
vertical to pass. B is the analyzer, placed at right angles, and 
causing darkness by stopping the rays vibrating in the vertical 
plane. If B be rotated sufficiently, the polarized ray passes 
readily and the light reappears. 

Having set the polarizer and analyzer at the angle to stop 
both planes, it is possible to turn the ray of light to the trans- 
mitting plane by putting between them certain substances which 
rotate the rays to the right or left. Among the substances having 
this rotating property are quartz, the sugars, proteins, and biliary 
acids; they are classed as optically active. Those substances that 
cause opacity or a shadow when the analyzer is rotated to the 
right (expressed by the sign + ) are said to be dextrogyrous (such 




Fig. 21. — Action of polarizer and analyzer. 

as dextrose), while those so acting by the opposite movement 
(expressed by the sign — ) are called levogyrous (as levulose). 
Having determined the direction and the number of degrees of 
rotation of the plane of polarized light caused by a solution, its 
composition and concentration may be ascertained. The degree 
of rotation corresponds to the amount of the optically active sub- 
stance in solution; that is to say, the twist given to the ray depends 
on the number of molecules which it passes on its way. In the 
polariscope the polarizing and analyzing crystals used are specially 
cut rhombs of Iceland spar, called NicoVs prisms. These deflect 
the ordinary ray from the straight path and extinguish it, but 
permit the extraordinary ray to pass through. 

Laurent's half=shadow polarimeter is the instrument seen 
in section in Fig. 22. At A is a yellow flame, which is best ob- 
tained by heating a sodium salt in a Bunsen burner; but a gas 
flame may be used and the monochromatic yellow color imparted 
as the light passes through the plate of potassium bichromate at 
B. It then passes through the Nicol's prism (P), the rays in the 
horizontal plane emerging as polarized light; those in the per- 



6o 



LIGHT 



pendicular plane are deflected and stopped by a diaphragm. At 
D the light is modified by a diaphragm, one-half of which is 
covered by a thin plate of quartz, cut so as to have but little 
rotating power. The circle below D shows the diaphragm divided 
in perpendicular halves by the quartz plate. A tube of brass, 
i decimeter long, closed at both ends with disks of glass, is filled 
with the solution to be tested and inserted at T in the path of the 
polarized ray. 

The eyepiece (O) contains a lens and the analyzing prism (N) y 
the whole tube rotating on its long axis as the vernier arm is. 
moved around a circle graduated in degrees. When the tube (T) 




Fig. 22. — Laurent's half-shadow polarimeter. 

contains water and the vernier is at o°, the eyepiece being focused 
on the vertical line of the diaphragm, the two sides should be 
equally illuminated, as in the circle i. If one side be darker, then 
the polarizer must be rotated by the screw at P until both sides 
are alike. When a solution of sugar or albumin, or other optically 
active substance, is introduced into the tube only one side of the 
diaphragm is unshaded, as in circles 2 albumin and 3 sugar. By 
moving the vernier around the circle, to the left for 2 and to the 
right for 3, both sides of the diaphragm become equally illu- 
minated, as in circle 4, and the reading of the instrument gives 
at once the angle of rotation of the solution in the tube (T). 

The expression specific rotating power or specific rotation of a. 



POLARIMETRY 6 1 

substance means the extent of rotation (expressed in degrees) 
caused by i gm. of that substance dissolved in i c.c. of liquid, 
examined in a tube i decimeter long. 

If a be the observed angle, p the number of grams of substance 
in i c.c, / the length of the tube in decimeters, and the specific 
rotation for the yellow light (D) of the spectrum be designated by 

(a) D , then the formula would be (a) D = ±~ r The specific rota- 
tion of glucose is stated as (a) D = +52. 5 ; that is, a rotation of 
the ray to the right 52.5 ° is caused by 100 gm. of the substance 
in 100 c.c. of water. Therefore, with a one-decimeter tube i° = 

— - gm. in 100 c.c. Example: A specimen of diabetic urine at 

o° showed the disc half-shaded, as at 3, Fig. 22, and using a 
one-decimeter tube (T, Fig. 22) required 2 of dextrorotation 

to get equal illumination, as in circle 4, Fig. 22, then =— — 

= 3.8 per cent, glucose. 

The polarimetry of urine requires that the specimen should 
first be made free of albumin, which rotates as far to the left 
(circle 2, Fig. 22) as glucose does to the right (circle 3, Fig. 22), 
its formula bring (a) n = — 56 °. If albumin be detected, then 
the urine must be acidulated, boiled, and filtered before testing 
with the polarimeter. 

In most cases of diabetic urine the concentration of sugar is 
small, and the longer tube (2 decimeters) is used to contain it. 
With this tube the reading is divided by 2 before the percentage 
calculation is made; some medical polariscopes are graduated 
to read percentage of glucose direct. 

An accurate adjustment of the reading may require that the 
urine be decolorized. This is done simply by adding 1 drop of 
acetic acid and shaking with a test-tube full of urine a small piece 
of lead acetate and filtering off the precipitate. Another method 
is to put \ c.c. of washed blood-charcoal in a test-tube full of 
urine, then shake and filter. It must be remembered that a 
trace of maltose may be present, though rarely, and may increase 
the angle, as it rotates more than glucose — (a)^=+i4o°. It 
does not ferment so readily as glucose. Diabetic urine some- 
times contains /3-oxybutyric acid, which rotates to the left — (a) D = 
— 24. 2 — and hence may reduce the glucose reading or neutralize 
it altogether. The difference between the dextrorotation before 
fermentation and that afterward would show the presence and 
amount of the glucose alone. At room temperature 20 ° C. 
(68° F.) the specific rotation of cane-sugar is (a) D = +66. 5 ; 
malt sugar +137.0 ; levulose — 93. o°, and invert sugar — 20.2 °. 



62 THE CHEMICAL ELEMENTS 



THE CHEMICAL ELEMENTS 

Chemistry is that branch of science that deals with the prop- 
erties and composition of substances, and studies the phenomena 
attending changes of composition. 

When water by variations of temperature becomes ice or 
steam, it has undergone a physical change, due to the play be- 
tween two physical energies: cohesion and heat. When glass 
or sealing-wax is rubbed it acquires the property of attracting 
feathers, pith-balls, and paper, by virtue of a transient physical 
power, the electric energy. When iron is made red-hot or when it 
is magnetized, it remains iron still, but when it rusts it loses its 
magnetic qualities and is transformed into a substance of wholly 
different properties. The energy which rusts iron, which burns 
coal, which turns milk sour, which changes wine into vinegar is 
not physical, but chemical. 

The chemical energy or affinity acts between different kinds of 
matter, causing them to lose their characteristic properties in 
forming a new substance. While its operations are correlated 
with those of physical energy, it is peculiar in that it produces 
permanent change in bodies. The change is more profound than 
that induced by mechanical mixture. 

If powdered iron and powdered sulphur are mixed by tritura- 
tion in a mortar, to the naked eye a change in color is visible, the 
yellow and black making brown; but under the microscope we 
can distinguish the iron particles as separate from those of sul- 
phur. The particles of iron are still magnetic and can be removed 
by the touch of a magnet. The sulphur can be dissolved out by 
treating the mixture with carbon bisulphid. When, however, the 
original mixture is ignited, the iron and the sulphur unite by 
chemical affinity, and now the microscope fails to detect the 
two different substances; the magnet will not separate the iron, 
nor the carbon bisulphid dissolve the sulphur. Chemical energy 
is distinguished further by the fact that its action is limited to 
definite weights of matter, while a mechanical mixture can be 
made of ingredients in any proportion. 

All natural objects, suns, planets, the mineral strata of the 
earth, its bodies of water, and its aerial envelop, the living things 
that crowd its surface, the molecules and atoms, are held in place 
by an energy which manifests itself in the phenomena of gravita- 
tion, of cohesion, and of chemical affinity. Gravitation affects 
all forms of matter at all distances; cohesion acts on molecules at 
distances immeasurably small; chemical affinity acts • upon the 
minute atoms at insensible distances, causing such transformations 



THE CHEMICAL ELEMENTS 



63 



of the bodies acted upon that they can no longer be recognized 
by ordinary means. 

Elements and Compounds.— All forms of matter may be 
divided into two classes, compounds and elements. Most natural 
objects are compound — that is, bodies that can be decomposed 
into simpler kinds of matter. They consist of two or more ele- 
ments united by chemical affinity. Elements are the simplest 
constituents of a compound into which it is decomposed. While 
some of them occur free in nature, most of them are obtained by 
chemical separation of the parts of a compound. The resolution 
of a compound into its parts is called analysis, while the building 
up of a compound by combining its parts is called synthesis. 
Every element has a constant combining equivalent (p. 114) and 
has never been known to enter any compound in less proportion 
than this equivalence. It is also characterized by a definite spec- 
trum (p. 55). 

The diversity of matter in the more than 300,000 forms seen 
in the universe is due to variations in the kind and the proportion 
of the elements engaged. Science has as yet found 80 odd simple 
bodies or elements. 1 Of the elements now identified not more 
than 40 are of any practical medical importance; the others are 
rarely encountered. Those deserving attention will be found 
in the following tables, each accompanied by its symbol, which 
is either the initial letter of the English or Latin name, or that 
letter combined with a significant small letter taken from the name. 
The combining equivalents in round numbers are given in the 
third column. 

The elements are broadly divided into two classes: non-metals 
and metals, each having properties generally characteristic. Non- 
metals physically have low specific gravity and are poor con- 
ductors of heat and electricity; chemically they form acids. Metals 
have high specific gravity and metallic luster, are good conductors 
of heat and electricity, and form bases. 

Some Non-metals 



Name. 


Symbol. 


Combining 
equivalents. 


Name. 


Symbol. 


Combining 
equivalents. 


Oxygen 





16 


Fluorin 


F 


19 


Hydrogen 


H 


I 


Chlorin 


CI 


35-5 


Nitrogen 


N 


H 


Bromin 


Br 


80 


Carbon 


C 


12 


Iodin 


I 


127 


Boron 


B 


II 


Sulphur 


S 


32 


Silicon 


Si 


28 


Phosphorus 


P 


3i 



1 There is no escape from the conclusion that the cathode electric rays of a 
Crookes tube are disembodied charges of negative electricity or electrons, in which 
the subdivision is carried much further than in the ordinary molecule or even 
atom. The atoms of different chemical elements seem to be different aggregations 
of the same primordial electrons. The phenomena of radio-activity exhibited by 
the element radium are explained on p. 247 by this hypothesis. 



6 4 



THE CHEMICAL ELEMENTS 



All of the above, except hydrogen and oxygen, form acids 
when united with those two elements. 



Name. 



Symbol. 



Potassium 


K (Kalium) 


Sodium 


Na (Natrium) 


Lithium 


Li 


Barium 


Ba 


Strontium 


Sr 


Calcium 


Ca 


Magnesium 


Mg 


Aluminium 


Al 


Arsenic 


As 


Antimony 


Sb (Stibium) 


Bismuth 


Bi 


Cadmium 


Cd 



Some Metals 




Combining- 
equivalents. 


Name. 


sy-boi. e c q r v b a si 


39 


Zinc 


Zn 65 


23 


Nickel 


Ni 58 


7 


Cobalt 


Co 59 


137 


Iron 


Fe (Ferrum) 56 


87.5 


Manganese 


Mn 55 


40 


Chromium 


Cr 52 


24 


Tin 


Sn (Stannum) 118 


27 


Copper 


Cu ( Cuprum) 63 


75 


Lead 


Pb ( Plumbum) 207 


120 


Mercury 


Hg (Hydrargyrum) 200 


208 


Gold 


Au (Aurum) 197 


112 


Platinum 


^ 195 



Some of the above-named metals, such as arsenic and antimony, 
might with equal reason be classified along with the non-metals 
nitrogen and phosphorus, which they closely resemble in their 
chemical traits. Most of the true metals will form bases by union 
of their oxids with water. 

Chemical compounds are usually considered in two great 
classes, the Inorganic and the Organic, though the line of demar- 
cation is one made for convenience and is not drawn by nature. 
Inorganic compounds are of mineral origin, not requiring a living 
organism to produce them. Examples are water, lime, and com- 
mon salt. Organic compounds are those which, as found in nature, 
are produced exclusively by the action of organized animal or 
vegetable life. Examples are fat, albumin, starch, and sugar. 
As carbon is invariably present in organic substances, organic 
compounds are sometimes called carbon compounds. Beside 
carbon, they usually contain oxygen and hydrogen, and very often 
nitrogen. Owing to the marked traits of these four non-metals, 
they are especially fitted for study as types illustrating the prin- 
ciples of chemical philosophy. Hence they are often termed 
Typic Elements. They are of the greatest importance to the 
physiologist in his study of nutrition and animal heat. On these 
accounts in the following pages extended treatment is given to 
the compounds of these elements. 

The body of a living animal contains about 60 per cent, water 
and 40 per cent, solids. They exist as more or less complex com- 
pounds of elements, which are abundant in the following order of 
percentage: Oxygen, 66.0; carbon, 17.5; hydrogen, 10.2; nitrogen, 
2.4; calcium, 1.6; phosphorus, 0.9; sodium, 0.3; chlorin, 0.3; sul- 
phur, 0.2; magnesium, 0.05; iron, 0.004; an d traces of iodin, 
fluorin, silicon, copper, manganese, and lithium. 



OXYGEN 65 

Notation. — The symbols H, O, etc., stand not only for the 
element, but for a chemical unit of the element. When more 
than one unit is expressed a large numeral is written before, mul- 
tiplying all the symbols that follow it, as 2H, or a small numeral 
is placed to the right and below the symbol, as H 2 , for 2 units of 
hydrogen. To express admixture of elements the plus sign is 
used, thus H 2 +0 means that 2 units of hydrogen are mixed with 
1 of oxygen. To express union or combination the symbols are 
put as close together as the type will go; thus 2H 2 means two 
parts of the compound formed when hydrogen, two units, and 
oxygen, one unit, unite by chemical attraction. 



NON-METALS 



Classification. — It is assumed that the medical student is 
a beginner in chemistry, and as yet is unfitted to appreciate the 
reasons for arranging the elements according to the natural or 
scientific classification (see page 116). The considerations which 
make the most logical system desirable will be understood only 
after the principles of chemical philosophy have been studied. 
These principles will be elucidated in the course of studying the 
Typic Elements — oxygen, hydrogen, nitrogen, and carbon, and 
their compounds. These will be first considered in the order 
best suited for the intellectual needs of the student, though ref- 
erence will be made to the more systematic grouping given below: 

Group I. Hydrogen, unique (Monovalent). 

Group II. Halogens or the chlorin family : chlorin, bromin, iodin, and fluorin 
(Monovalent). 

Group III. The oxygen fa mily : oxygen, sulphur, selenium, and tellurium (Di- 
valent). 

Group IV. The nitj-ogen family : nitrogen, phosphorus, arsenic, and antimony 
(Trivalent). 

Group V. The argon family : argon, helium, neon, crypton, xenon. 

Group VI. The carbon family : carbon, silicon, (Quadrivalent). 

OXYGEN 

Symbol, O. Atomic weight, 16. 

History. — The discovery of oxygen was an incident in the 
study of the composition of the atmosphere. The early Greek 
philosophers regarded the air as an element, as they did the earth, 
fire, and water. 

Its complex nature was suspected when, early in the seventeenth 
century, the observation was made that by combustion in a 
5 



66 NON-METALS 

confined portion of air, the air lost weight, and that the remainder 
would support neither life nor fire. Priestley showed that by 
heating mercury in enclosed air for several days at a temperature 
near its boiling-point, the mercury was changed to a red powder, 
now called mercuric oxid, while the life-sustaining part of the 
air disappeared. In 1774 he found that by heating mercuric 
oxid a gas was liberated which, when mixed with the burnt-out 
air, would restore to it the properties of supporting respiration 
and combustion. 

This operation is performed in a hard glass reduction tube 
or retort, and the gas collected over water in a pneumatic trough, 
the mercury being condensed on the cooler part of the glass tube. 
The result may be written as follows: 

Mercuric oxid yields mercury and oxygen. 

Or, by short hand, 

HgO Hg +0. 

In 1775 Scheele discovered oxygen by heating manganese 
dioxid with strong sulphuric acid. 



2Mn0 2 


+ 


2H 2 S0 4 = 


= 2 MnS0 4 


+ 


2 H 2 


+ 


o 2 


Manganese 
dioxid. 




Acid 
sulphuric. 


Manganese 
sulphate. 




Water. 




Dxyge 



Preparation. — Many higher oxids, as manganese dioxid, 
Mn0 2 ; lead dioxid, Pb0 2 ; and barium dioxid Ba0 2 , yield a part 
of their oxygen when heated. Barium dioxid above 400 ° C. 

(752 ° F.) gives off half of its oxygen. 

Ba0 2 = BaO + O. 

Barium dioxid. Barium monoxid. 

This lower oxid, BaO, heated at a lower temperature in a cur- 
rent of air, takes up the oxygen it had lost. By alternating these 
processes oxygen is now manufactured on a commercial scale at 
a low cost. 

In the laboratory potassium chlorate is the source. When 
this compound is heated, it parts with its oxygen, leaving potassium 
chlorid in the retort. 

KCIO3 = KC1 + 3O. 

Potassium chlorate. Potassium chlorid. 

It is customary to employ a mixture of coarsely powdered 
manganese dioxid 1 part and potassium chlorate 2 parts. This 



OXYGEN 



6 7 



causes the KC10 3 to yield oxygen at a comparatively low tem- 
perature, 200 ° C. (372 ° F.). The manganese dioxid is not de- 
composed, though its presence causes the easy transmission of 
oxygen from the chlorate. 

Precaution. — The materials should be dry and free from 
organic dirt. Serious explosions have happened from the action 
of oxygen on the carbon of coal-dust or other impurities in com- 
mercial manganese dioxid. To guard against such accidents 




a small sample should be tested by heating with some potassium 
chlorate in an open test-tube. 

In preparing oxygen for inhalation it is advisable to free it 
from all traces of chlorin by passing the gas through potassium 
hydroxid in a wash bottle before collecting it in the gas bags or 
gasometer. Before removing the lamp withdraw the delivery 
tube from the water, if collected in a pneumatic trough, or the 
regurgitation of the water will cause an explosion. In making 
a quantity of the gas it is customary to use a copper retort for the 
potassium chlorate. In practice 250 gm. (8 oz., Troy) of the 
chlorate yields about 68 L. (18 gal.) of oxygen gas. 

Occurrence. — Oxygen is the most abundant element. It is 
found widely distributed in nature, forming one-fifth part of the 
volume of the air and eight-ninths, by weight, of all water. As an 
ingredient in most minerals it makes up nearly one-half of the 



68 NON-METALS 

weight of the earth's crust, and it is present in almost all animal 
and vegetable compounds. 

Physical Properties.— Oxygen is a little heavier than air, 
its specific gravity being 1. 10563 (air=i). It is an invisible gas, 
colorless, tasteless, and odorless. It is slightly soluble in water, 
0.04 volume dissolving in 1 volume of water at o° C. (32 ° F.). 
In the proportion of about 3 per cent, by volume it is dissolved in 
natural water at ordinary temperatures, and furnishes to the gills 
of fishes the amount needed for the aeration of their blood. It 
has been liquefied at — 118 C.( — 244.4 ° F.) under a pressure of 
50 atmospheres. These are called its critical values. 

Chemical Properties. — It has affinities of great power and 
wide range, combining with every element except fluorin and the 
argon group. As the air is practically one-fifth part oxygen 
diluted, all its chemical reactions are those of this gas. There 
is this difference only: the pure oxygen causes far more intense 
displays of energy. By attaching various combustibles to copper 
wire, first igniting them in the air and afterward plunging them 
into jars of pure oxygen, the contrast will show how much the 
diluent of the air mitigates the violent action of this gas. Sulphur 
will burn in the air with a pale blue flame of little luminous power; 
in oxygen, however, its flame is violet colored, emitting great light. 

S + o 2 = S0 2 

Sulphur. Sulphur dioxid. 

A piece of charcoal with a feeble spark and without flame, when 
immersed in oxygen, becomes a white, glowing mass and is in- 
stantly consumed in flames. A glowing chip of wood is a reagent 
in testing for oxygen and the reaction is its bursting into flame. 

C + o 2 = co 2 

Carbon. Carbon dioxid. 

If a piece of dry phosphorus the size of a pea be warmed in 
a deflagrating spoon and then burned in oxygen, its light is of 
insupportable brilliancy. 

P 2 + o 5 p 2 o 5 

Phosphorus. Phosphorus pentoxid. 

Fine iron piano wire or watch springs tipped with burning sulphui 
and set on fire in oxygen will burn with dazzling corruscations. 

3 Fe + 4 = Fe 3 4 

Iron. Iron tetroxid. 



OXYGEN 69 

The non-metals burning in oxygen yield oxids, which in the 
cases of sulphur, carbon, and phosphorus are gases that will dis- 
solve in the water in the jar, giving to it a sour taste and an acid 
reaction. Iron forms a solid compound without acid qualities, 
which leaves a rusty stain on the jar. Other metals form oxids, 
which are usually bases. 

The presence of free oxygen is revealed by adding to the sus- 
pected sample the colorless gas nitrogen dioxid, which unites with 
more oxygen to form red fumes of the higher oxids. Free oxygen 
is removed from mixtures of gases by means of its slow union with 
phosphorus or by making use of the absorption powers of a solu- 
tion of potassium pyrogallate. 

Physiologic Effect. — Oxyhemoglobin of the blood-corpuscles 
under the air-pump yields about two volumes of oxygen, which 
is so loosely associated as to be separable without destruction of 
the compound. This load is readily transferable to oxidizable 
substances. The muscles and, indeed, protoplasm in general, 
have the power of absorbing and storing up oxygen to be utilized 
in the transforming of chemical into other forms of energy. If 
an animal be enclosed in an atmosphere containing no oxygen 
it shortly dies. It is the only pure gas that will sustain respir- 
ation. At ordinary pressures no detriment follows its inhalation. 
When disease interferes with normal oxygenation of the blood 
benefit is obtained by enriching the air respired with about 60 per 
cent, of this gas. The livid appearance disappears under its 
judicious employment. 

Uses. — The gas is made portable by condensing 40 gallons in 
a small cylinder. By a rubber tube it is transmitted to a funnel 
held near the face of the patient. It is used in this way in the 
treatment of the later stages of pneumonia and consumption and 
in resuscitation from coal-gas poisoning. 

Law of Chemical Combination.— When Priestley, on the dis- 
covery of oxygen, resorted to the balance, he was able to prove 
that mercuric oxid contains an unvarying amount of oxygen joined 
to an unvarying proportion of mercury. When the two elements 
in these fixed proportions were caused to combine they produced 
the compound. Any excess of either would not enter into the 
union. 

Potassium chlorate, when analyzed and its constituents weighed,' 
is found to be composed of 39 parts of potassium, 35.5 parts of 
chlorin, and 48 parts of oxygen. All specimens of potassium 
chlorate have exactly this composition. 

When the composition of a salt is once ascertained, the knowl- 
edge thus obtained applies to all samples of that salt. Common 



70 NON-METALS 

salt is, always and everywhere, sodium 23 parts and chlorin 

35-5 P arts - 

When it is desired to make note of a chemical operation in 

shorthand, symbols are used to express both the nature of the 

elements and the relative weights engaged. Thus the equation, 

KC10 3 =KCl + 30, 

written out in full, would read: potassium chlorate 122.5 (potas- 
sium 39 parts, chlorin 35.5, and oxygen 48) yields potassium 
chlorid 74.5 (potassium 39, chlorin 35.5) and oxygen 48 parts. 

If these figures on each side of the equation are added, they 
will be found to be equal, though the = mark is not used in an 
algebraic sense; it means gives or yields. 

Reactions. — We have learned that mercury, heated in air, 
takes up oxygen, forming mercuric oxid, Hg+0 = HgO. This 
is an illustration of the first kind of reaction, called combination. 
The second kind is called decomposition, as in the case of KC10 3 , 
given above, which reverses combination. The third kind is 
double decomposition, when two or more compounds break up 
and form two or more others, thus: 

KC1 + AgNO s = AgCl + KNO3. 

This is read, potassium chlorid added to silver nitrate gives silver 
chlorid and potassium nitrate. 

When the composition of many compounds is studied it is 
found that the most satisfactory unit for expressing the numeric 
ratios of the combining weights is that of hydrogen, the lightest 
element. The different symbols stand, then, not only for the name, 
but also for certain relative weights or proportions (H being 1) 
in which the elements unite, or those in which they displace one 
another in compounds. 

H stands for 1 part of hydrogen, O for 16 parts of oxygen, 3 
for 3 times 16 or 48 parts of oxygen, K for 39 parts of potassium, 
S for 32 parts of sulphur, C for 12 parts of carbon. 

A convenient statement of the facts just referred to is called 
the law of definite or constant proportions or combination: 

11 A definite chemical compound always contains the same 
elements united in the same proportions." 

This law, first stated by Dalton in the eighteenth century, by 
numerous experiments became more and more assured, and the 
great generalization gradually took shape — that matter is inde- 
structible. So far as our observation goes, it is not created, nor is 



OXYGEN 71 

it destroyed. It may change its form a thousand times, but does 
not change its ultimate nature, neither gaining nor losing. 

When a piece of charcoal is burned in oxygen it disappears 
from view, but if the product contained in the vessel be weighed 
it will be found to equal exactly the weight of the original 
materials. The carbon has been taken into an invisible gaseous 
compound, carbon dioxid. From this state it can be recovered 
in the original amount as fine black dust by burning sodium in 
the gas. The sodium liberates the carbon, taking the oxygen 
away from it. 

When KCIO3 has yielded its oxygen there is left in the retort 
KC1, potassium chlorid, composed of potassium 39 parts and 
chlorin 35.5 parts. There is a familiar salt used in medicine, 
potassium iodid, which is composed of potassium 39 parts 
and iodin 127. Now when chlorin and iodin unite to form 
iodin chlorid, they do so in the same relative weight, 35.5 to 
127. Dependent upon facts of the same character is the corol- 
lary to the first law, which is called the law oj equivalent pro- 
portions: 

" The proportions in which any two elements unite with a third 
are the same in which they unite with each other." 

Hence it is said that chlorin 35.5, iodin 127, oxygen 16, sodium 
2^, potassium 39, are equivalent to each other, taking hydrogen 
as unity. Every element has an assigned equivalent weight, 
which rules the proportions of its combinations with other 
elements. 

Chemical Arithmetic. — The constancy of the proportions in 
chemical compounds definitely distinguishes them from mechan- 
ical mixtures. When active chemicals are mixed in any other than 
the exact proportion, the excess is inert. Chemistry is based so 
surely upon numeric laws that calculations can be made for chem- 
ical operations as for those of other exact sciences. 

Suppose the problem to be: how much of the gas would be 
obtained by heating a weight of, say 250 gm. (8 oz., Troy), of 
potassium chlorate. The equation, already given, is as follows: 

KCIO3 = KC1 + 3O. 

From the numeric values given for this equation (p. 70) we 
calculate that 122.5 parts of KC10 3 will, when heated, give up 48 
parts of oxygen. By a sum in rule-of-three (ratio and proportion) 
we easily find how many would be given by 250 gm. of KC10 3 : 

122.5 : 250 -48 : x 
x = 97.95 gm. of oxygen. 



72 NON-METALS 

If it be desired to know the number of liters represented by the 
weight of 97.95 gm. an additional calculation is required. Experi- 
ments show that 22.4 L. of any normal gas weigh a number of 
grams equal to twice the combining weight. Then one-half, or 
1 1.2, would equal the combining weight, which, with oxygen, is 
16. Therefore, 

16 : 97.95 :: 11. 2 : x 

# = 68.56 L. of oxygen evolved from 250 gm. 
of potassium chlorate. 

Relations of Other Forces to Chemical Energy. — Melting 

solids by heat, or at higher temperatures vaporizing them, favors 
chemical change. Furthermore, all changes of decomposition or 
of combination are set in action by the physical agencies, radiant 
energy, heat, light, electricity, magnetism, and mechanical force. 
These are convertible into one another and are but forms of the 
one energy in the universe. 

When potassium chlorate is heated to a high degree its par- 
ticles are freed from their cohesion and chemical action causes 
the potassium and chlorin to form a different compound, setting 
the oxygen free. 

At ordinary temperatures carbon remains in oxygen for a long 
time without visible change, though if coal be finely divided and 
packed so as to confine the heat that is produced by its gradual 
oxidation, it ignites spontaneously. Whenever carbon is heated 
to ignition there is immediate union with the oxygen. Moreover, 
the union is itself attended by the evolution of still more heat. In 
the oxygen experiments the degree of heat is so great that a brilliant 
light is emitted. Burning in air is the same as burning in oxygen, 
though the visible heat is less because the diluent nitrogen in air 
takes up the heat without helping on the process, while in pure 
oxygen the chemical energy of that active gas is increased by its 
being heated. The term combustion is applied to this evolution 
of heat and light by chemical action. Combustion is due to the 
conversion of intrinsic or chemical energy into heat energy. The 
substances that burn are called combustible. The process con- 
verts them into incombustible products, such as carbon dioxid and 
sulphur dioxid. All chemical actions are attended by changes 
of temperature, but in writing equations it is customary to omit 
mention of the energy of heat consumed or evolved. 

The amount of heat evolved or absorbed in the chemical change 
of a substance is definite and is always the same from given weights 
of the reagents. If rapid union be induced, as in combustion, 
then a higher temperature is noted, but no more heat in quantity 
is given off than when union is gradual. The number of heat 



OXYGEN 73 

units or calories (p. 34) obtained is the same whether combustible 
bodies are oxidized by degrees or whether the same substances are 
burnt up. When coal is burned in a grate we have an example of 
heat production by quick oxidation. When carbon compounds 
are consumed in our bodies by their union with the oxygen of the 
blood obtained from respired air, we have an instance of heat 
production by slow oxidation. A given weight of the combustible 
will yield the same number of heat units in both cases. One gram 
of a carbohydrate, such as starch, burned with oxygen in a calor- 
imeter, liberates 4100 calories. In the animal body the same 
weight of starch is oxidized to the same products (carbon dioxid 
and water), liberating the same number of calories. Combustion 
means that the heat is given off in a short period, evincing great 
intensity. The process has high velocity. Oxidation in the animal 
body is distributed through greater periods and regulated so that 
the escape of heat is compatible with life; indeed, is necessary to it. 
It is dissipated as fast as it is produced. The velocity is so low 
that the heat never reaches sufficient intensity to ignite the elements 
engaged. 

To use a homely illustration: if a bucket slowly leaks, a gallon 
of water can be poured into it at the same rate (slow oxidation) 
and no water accumulates, but if poured quickly (combustion) 
the water level rises, stands high in the bucket, and may even 
overflow. Two-thirds of the amount of heat generated in the 
body is converted to other forms of energy and escapes by radiation, 
the remaining one-third finds outlets in the hot urine and feces, 
which contain much more heat than the cool water drunk; in the 
latent heat of vaporizing the water of perspiration and respira- 
tion; and in warming the air inhaled, which has high specific 
heat (p. 34). 

The Heat of Decomposition. — The heat consumed in 
slowly oxidizing mercury to form mercuric oxid is the same in 
amount as that required to decompose it into its elements. To 
form HgO it takes 30,660 calories, and to separate its elements 
Hg and O the same number of heat units must be used. 

Work=energy of Oxidation. — Heat is a source of mechan- 
ical motion, as in the steam engine, and, on the other hand, the 
arrest of motion causes heat. They are reciprocally convertible 
in definite amounts, a certain amount of work-energy producing 
a corresponding amount of heat-energy and vice versa. This 
numeric relationship is expressed thus: one calorie equals 0.426 
kilogram-meters, which is to say, that the amount of heat required 
to warm one gram of water one degree Centigrade of temperature 
will, when converted to work-energy, lift 1 kilogram weight through 
0.426 meters. 



74 NON-METALS 

In order to have but one unit for all the different forms of energy, 
that of Joule has been chosen. Thus i calorie (cal.) equals 4.18 
joules (j.), or, reversing the statement, 1 joule = 0.239 cal. 

Large amounts of energy are expressed by kilo joules (kj.) or 
1000 joules. By experiment it is found that the heat of combustion 
of a combining weight of carbon equals that which produces 
406 kj. of work-energy. The equation C + 2 =C0 2 + 4o6 kj. 
reads thus: the sum of the intrinsic energy of 12 gm. of carbon 
and 32 gm. of oxygen equals the energy of 44 gm. of carbon dioxid 
plus 406 kj. This 406 kj. may be utilized in engines suited for 
converting heat to motion, or in animals for maintaining the work- 
energy and animal heat. The energy of C0 2 , an incombustible 
product, is less than that of the combustible C and O by 406 kj. 
Hence to restore C0 2 to the original state of free C and free O this 
energy must be supplied. In nature the source of this energy is the 
sun, which, acting upon the leaves of plants as its instruments, 
breaks up the C0 2 of the air, storing C in the plant and giving 
O back to the air. 

OZONE OR ALLOTROPIC OXYGEN 

Symbol, O s . Molecular weight, 48. 

When the sparks of an electric machine are passed through 
dry air or oxygen a peculiar odor is developed. This odor has 
been observed after thunder-storms or when flint and steel are 
struck. The odoriferous substance is named ozone (Greek, 
ozein, to smell). 

Occurrence. — Owing to its odor, ozone can be recognized in 
the air when present in the proportion of only one part to a hun- 
dred thousand. Delicate tests detect it in sea air, at the seashore, 
where water evaporates from sand and where the waves are broken 
into spray; in the country, and especially in the air of pine forests. 
On the windward side of cities it can be found, but all trace dis- 
appears on the leeward side. The organic impurities emanating 
from cities destroy the ozone. 

Preparation. — Ozone can be produced by slowly oxidizing 
phosphorus in moist air. A stick of phosphorus, freshly scraped, 
is put in a wide-mouthed bottle of air or oxygen and half covered 
with water. The bottle is closed for an hour or two, when, at the 
end of that time, the ozone is present. 

Another method is by adding 2 parts of potassium perman- 
ganate to 3 parts of sulphuric acid. 

Siemen's induction tube generates ozone by discharging elec- 
tricity silently through an atmosphere of dry oxygen. A tube of 
glass covered with tinfoil, like the outer coat of a Leyden jar, encloses 



OZONE OR ALLOTROPIC OXYGEN 



75 



a 



the space to be filled with oxygen. In the axis of this tube is 
another, smaller and lined inside with tinfoil like the inner coat 
of a Leyden jar. The dry oxygen slowly traverses the space 
between the tubes, while the electric 
discharge from either a friction ma- 
chine or an induction coil passes 
invisibly from the tinfoil on one tube, 
through the glass and oxygen, to the 
tinfoil on the other tube. In its 
transit a portion of the odorless oxy- 
gen acquires the odor of ozone and 
will oxidize substances that resist the 
pure oxygen. 

Instead of tinfoil as a condenser, 
sulphuric acid is used in the appa- 
ratus shown in Fig. 24. A tall glass 
cylinder containing sulphuric acid has 
immersed in it a bent tube having 
one limb larger than the other. 
The wider limb has an inner tube 
containing sulphuric acid. Elec- 
trodes of platinum dip into the sul- 
phuric acid, inside and outside. 
While an induction coil discharges 

between the electrodes, dry oxygen (0 2 ) passes in at a and comes 
out ozonized (0 3 ) at b. 

If ozone be passed into a solution of potassium iodid, the iodin 
is liberated and potassium hydroxid formed: 

+ o 2 

Oxygen. 




Fig. 24. — Ozone generator. 



2KI + 


H 2 


+ 


3 = 


2KOH 


+ 


I 


Potassium 
iodid. 






Ozone. 


Potassium 
hydroxid. 




Iod 



The least trace of free iodin can be detected by a solution of 
starch, which will turn a deep blue color. Schonbeiri 's test-paper 
is made by saturating pieces of white filter-paper with a mixture 
of solutions of starch and potassium iodid. If dried and kept in 
tight bottles, this paper is a ready test for ozone in the air. To 
use it, the paper must be moistened with distilled water and sus- 
pended in an exposed place to the current of air to be tested. 
This test is liable to a fallacy from the fact that when either chlorin 
or nitrogen tetroxid is present iodin is liberated and the same 
color reaction ensues. Ozone, however, is peculiar in yielding 
the alkali potassium hydroxid, or KOH, of the equation given 
above. It is an improvement on Schonbein's method to apply 
litmus instead of starch to prove that the potassium iodid has 



76 NON-METALS 

been decomposed by ozone. A solution of potassium iodid col- 
ored with a reddish-violet litmus and exposed in a shallow white 
dish for several hours will detect ozone in the air very readily. 
A control experiment should be conducted with the portion of 
the same litmus solution without the iodid. Another convenient 
method is to expose violet litmus-paper moistened with a solution 
of potassium iodid. If ozone be present, this test-paper will be 
turned blue from the alkaline hydroxid; but the same paper wet 
with distilled water will be unaffected. 

Properties. — Ozone as a gas is colorless, having an odor like 
that of chlorin. It has been liquefied at — 105 C. (—157° F.), 
with a pressure of 125 atmospheres, and is then of blue color. 
As ordinarily dealt with, it is always largely diluted with oxygen. 
In the dry state it can be kept unchanged, though its intrinsic 
energy gives it a tendency to explode into the state of ordinary 
oxygen, developing heat. At a temperature of 250 C. (482 ° F.) 
it is reconverted into oxygen. It is soluble in turpentine and 
sparingly so in water. 

Its chief chemical attribute is that of an oxidizing agent. By 
it elementary phosphorus, sulphur, and arsenic are oxidized to 
acids, and ammonia to nitric acid. Metals that do not rust in 
the air, such as mercury and silver, soon lose their brilliancy in 
ozone. Only gold and the members of the platinum group resist it. 

Paper made black with lead sulphid becomes white, the ozone 
changing the sulphid, PbS, to the white sulphate, PbS0 4 . 
Organic substances, such as cork and rubber, are corroded by it;, 
organic colors are bleached and gases of foul odor decomposed. 
It is a strong irritant to the air-passages, causing acute catarrhal 
symptoms even when the air contains so small an amount as 7 
parts in the 100,000. 

Nature of Ozone. — When oxygen is ozonized by exposure 
to electric discharges its volume is diminished and its density 
increased without the application of cold or heat, but when the 
ozone is heated to 300 ° C. (572 ° F.) it regains its volume while 
losing its characteristics as ozone. Three volumes of oxygen are 
condensed to form two of ozone; hence it is sometimes called 
condensed oxygen or allotropic oxygen. 

Allotropism. — When an element presents itself in two or more 
different modifications, the property is termed allotropism. There 
are allotropic forms of oxygen, sulphur, phosphorus, carbon, iron, 
etc. To explain the fact of condensation when oxygen takes the 
form of ozone resort is had to the theory of the molecular con- 
stitution of matter. Matter is assumed to be composed of small 
separate particles called molecules, which are usually groups of 
two or more smaller particles, called atoms. Many facts sustain 



HYDROGEN 77 

the law of Avogadro: "Equal volumes of elementary gases contain 
an equal number of molecules." The condensation of three 
volumes of oxygen to two of ozone is then accounted for by assuming 
that in an equal volume the ozone contains one-third more atoms, 
which must be accommodated in the equal number of molecules 
by making the molecules heavier. If the molecule of oxygen is 
symbolized by 2 , then that of ozone becomes 3 . Three mole- 
cules of oxygen then contain six atoms in three groups of two each. 
When they change to two molecules of ozone, they contain the 
same number of atoms, but in two groups, containing three atoms 
each. 

Carbon dioxid is produced when carbon is burned, whether in 
oxygen or ozone, but the number of the calories produced is very 
different in the two cases. More heat is given off by combustion 
in ozone than in oxygen — proof that the molecule of ozone has 
more intrinsic energy. Stated as an equation: Ozone = oxygen + 
energy. Allotropic elements may be regarded as 'those which 
under varying conditions take up different amounts of energy and 
thereby show a difference of properties. 

In the equation below the facts are represented on the theory 
of molecules and atoms: 

o 3 = o 2 + O. 

The 3 represents molecular ozone which yields 2 , one molecule 
of ordinary oxygen, and O, one atom uncombined, said to be 
nascent oxygen, which has an extraordinary readiness for a chem- 
ical union. In terms of the molecular theory allotropism is the 
property of an element, under different circumstances, to appear 
in molecules which have a difference in their atomic constitution. 

HYDROGEN 

Symbol, H. Atomic weight, 1.01. 

Occurrence. — Hydrogen exists free in the gaseous emanations 
from volcanoes, certain mines, "natural gas," and petroleum 
wells. As a product of fermentation of organic matter it is found 
in gastric and intestinal flatus. Its peculiar "lines" are seen in 
the spectra of the sun and various stars. 

Combined with other elements, hydrogen is exceedingly abun- 
dant. With oxygen it forms one-ninth of the weight of all the 
water on the globe; with nitrogen it is present in the air as ammonia; 
with sulphur it makes the gas hydrogen sulphid, present in sulphur 
waters. In organic nature it occurs not only in the hydrocarbons 
and the carbohydrates, but in almost all animal and vegetable 
substances. 



78 



NON-METALS 



Preparation. — i. By Electrolysis. — If a current of electricity 
be passed through water by means of platinum electrodes pure 
hydrogen bubbles off at the negative pole and oxygen at the 
positive, two volumes of the former to one of the latter (Fig. 25). 
The hydrogen is identified by its taking fire when lighted, the 
oxygen by its causing a glowing splinter of wood to burst into 
flame. The current is usually obtained from a battery of five or 
more galvanic cells — a combination of zinc and carbon plates, 
immersed in a liquid that acts upon the zinc. The chemical 
action in the battery is transformed into electricity, which is trans-, 
mitted by the conductors to the apparatus for electric decom- 
position. The process of separation of the constituents of a com- 
pound by electricity is known as electrolysis.. 
By means of this process the most obstinate- 
compounds have been resolved into their- 
elements under the conditions stated on p. 50.. 
The substance must be a conductor of 
electricity — i. e., an electrolyte. Pure water 
possesses this property in such an exceedingly 
small degree that it is regarded as a non-con- 
ductor. Its conductivity is improved by 
adding to it one-fourth part of sulphuric acid, 
which furnishes the ions necessary for con- 
ducting the current. 

2. By the Action of Various Metals on 
Water. — The affinity of metals for oxygen 
can be used in the decomposition of water 



Fig. 25. — Apparatus 
for the electrolytic decom- 
position of water, yield- 
ing hydrogen and oxygen 
separately. • 





Fig. 26. — Potassium decomposing water. 



for liberating hydrogen. Most metals act very slowly at ordinary 
temperature, but potassium and sodium decompose water very 
promptly. They unite with oxygen with such violence that the 
free hydrogen is inflamed. A piece of potassium or sodium the 
size of a pea thrown upon water will float about (Fig. 26), first 
melting into a silvery globule, hissing hot, then glowing, and 
finally igniting the free hydrogen. If the water has been tinctured 
with red litmus, it will turn blue from the formation of sodium, 
hydroxid. 

+ Na = NaHO + H.. 

Sodium. Sodium hydroxid. 



H 2 



HYDROGEN 



79 



In order to collect the hydrogen unignited a test-tube or glass 
cylinder should be filled with water and inverted with the open 
end immersed in a trough of water. Small pieces of sodium 
wrapped in filter-paper can then be held by forceps underneath 
the mouth of the test-tube. The gas is given off and collects above 
the surface of the water, forcing the water out of the tube. To 




Fig. 27. — Hydrogen disengaged from water by sodium. 

prevent explosions the sodium should be cut into pieces no larger 
than a split pea. In Fig. 27 the sodium is held under water by 
a wire-gauze spoon which permits the gas to rise into the cylinder. 

3. To get hydrogen for manufacturing purposes on a large 
scale the affinity of iron for oxygen is utilized. Here high heat is 
required. Steam is passed over iron turnings heated to redness in 
an iron tube. 

3 Fe + 4 H 2 = Fe 3 4 + 4 H 2 

Iron. Water. Iron tetroxid. Hydrogen. 

The iron is oxidized to the tetroxid and the hydrogen passes 
out to the collecting apparatus. If charcoal be used instead of 
iron at a high heat, a gas, carbon monoxid, is formed, and the 
two gases can be utilized as sources of heat and light. 

C + H 2 = CO + H 2 . 

Carbon monoxid. 

4. Hydrogen for the laboratory is customarily prepared by 
the reaction of some acid upon a metal. The acids all contain 
hydrogen and have the common characteristic of giving it up 
easily, taking a metal in exchange. The most convenient materials 
are zinc and dilute sulphuric acid. 



Zn 

Zinc. 



+ 



H 2 SQ 4 = 



ZnSO, + H, 



Acid sulphuric. Zinc sulphate. 



8o 



NON-METALS 






Zinc sulphate remains in solution, and the hydrogen is set free. 
If hydrochloric acid be used, then 

Zn + 2HCI = ZnCl 2 + H 2 . 

Acid hydrochloric. Zinc chlorid. 

These reactions are illustrations of substitution. The zinc is 
substituted for the hydrogen, and there is a new arrangement of 
the elements (Fig. 28). 

To perform this operation the zinc, in small pieces, is put into 
a glass flask or two-necked bottle. The stoppers of rubber or 
cork are perforated for tubes. One has a funnel outside, the 
lower end reaching nearly to the bottom of the flask. The other 
tube is short within the flask and bent outside at an angle con- 
venient for the attachment of a delivery tube. When the appa- 
ratus is tightly closed the sulphuric acid, diluted with five to six 




^ 



Fig. 28. — Hydrogen generator. 



parts of water, is poured through the funnel tube and a brisk 
effervescence begins immediately. The gas bubbles through the 
water of the pneumatic trough and collects in jars prepared for 
receiving it. 

Precaution. — Before collecting, it is advisable to allow suffi- 
cient gas to escape to be sure that the air has all been expelled 
from the collecting jars, otherwise an inflammable mixture is 
formed which, when ignited, explodes with dangerous violence. 
The test for this consists in obtaining a sample of the hydrogen 
at the trough by inserting a water-filled test-tube over the escaping 
bubbles. Pure hydrogen burns quietly at the mouth of the tube 
held mouth downward, while the occurrence of a slight explosion 
proves that some air still remains. 1 

Physical Properties.— Hydrogen is the lightest known sub- 

1 Prepared in this way from common zinc the gas always has an odor, due to the 
formation of gaseous compounds of hydrogen with arsenic and phosphorus present 
in the impure zinc, or to hydrogen sulphid when hot acid is used, or to nitrous and 
nitric oxids when the acid contains some nitric acid. 



HYDROGEN 



8l 



stance, being 14.47 times lighter than air. Its specific gravity 
is 0.06926 (air=i), and 1 liter weighs 0.0899 gm. It is trans- 
parent, colorless, odorless, and tasteless. It is not poisonous, but 
will not support life. If permitted to escape from a pressure of 
180 atmospheres at — 205 ° C. ( — 337° F.) it is a colorless, clear 
liquid, which freezes by its own evaporation, reaching a temper- 
ature of — 258 C. ( — 432.4° F.). It is nearly insoluble in water. 
It conducts heat and electricity better than any other gas. It is 
the most highly diffusible of gases, passing through a porous 
medium four times more rapidly than oxygen. Gas-bags of rubber, 
leather, membrane, or other porous material permit this diffusion 
with such freedom that in a short time the contents of the bag 
become an explosive mixture, consisting of hydrogen and oxygen 
obtained from the air. 

If the metal palladium is used as the negative electrode in the 
electrolysis of water, 980 volumes of hydrogen will be retained by 
it. By applying heat the metal gives up this occluded gas in a very 
active condition, similar to the state of hydrogen just free from 
chemical combination. 

Chemical Properties. — While hydrogen and oxygen resem- 
ble one another in physical properties, chemically they are oppo- 
sites and have a great attraction for one another. Hydrogen, 
however, is unique in its affin- 
ities, resembling the metals 
more than the non-metals, 
combining with chlorin, ni- 
trogen, sulphur, and carbon. 
It does not support combus- 
tion, but burns with a non- 
luminous blue flame, hotter 
than that produced by any 
other burning substance in 
equal weight. In combus- 
tion two volumes of it unite 
with one volume of oxygen 
to form two volumes of 
water vapor. If the gas be 
dried, by passing it through 
a desiccating tube, and then 
ignited at the terminal jet 
(Fig. 29), it burns with a pale 
flame, depositing moisture 
on the glass bell-jar. Mixed 

with chlorin, hydrogen explodes in the sunlight; with oxygen it 
explodes violently by the touch of a flame or an electric spark. 




Fig. 29. — Water formed by burning hydrogen. 



82 NON-METALS 

In the oxyhydrogen blowpipe a blast of oxygen is blown through 
the hydrogen flame; at its temperature of 2000 C. (3632 F.) 
quartz and ruby are fused. The lime light for stereopticons is 
made by heating lime in it to incandescence. 

Hydrogen is a reducing or deoxidizing agent. That is to say, 
it will take oxygen from oxids, reducing them to lower oxids or 
to the metallic state. Copper oxid or iron oxid at a red heat in 
a stream of hydrogen parts with the oxygen, forming water and 
the free metal: 

Fe 3 4 + 4 H 2 = 4 H 2 + 3 Fe. 

Reversible Processes. — Red-hot iron oxidizes in steam; the 
water giving oxygen to the iron is reduced to hydrogen. On 
the other hand, to produce the purest form of iron, such as is used 
in medicine under the name reduced iron, hydrogen is passed over 
red-hot iron oxid (p. 79). This mutual play, by which substi- 
tution and reformation can be made to occur at will, is expressed 
in an equation which can be read either way, the double arrow 
meaning that it is reversible: 

water + iron -*-^- hydrogen + iron oxid. 

In any chemical process we must consider not only the essential 
nature of the substances engaged, but also another factor — the 
active mass or concentration, or, to state it more accurately, the 
ratio of substances present. If the amount of hydrogen is rel- 
atively large the equation should read from right to left, but if 
the ratio of water vapor predominates in amount the reading is 
reversed. To use a homely illustration: a man may carry a pail 
of water, but a flood of water will carry away the man. 

Mass-action. — The law of mass-action is that chemical action 
is determined by the amounts 0} the substances acting in unit-volume , 
or by the concentrations present. 

When the operation is conducted in an apparatus that does not 
permit the escape of the hydrogen nor the condensation of steam 
to water, the point at which the oxidation of iron by water vapor 
comes to a halt is when a definite ratio is reached between the 
hydrogen and the water vapor present. This ratio is the same as 
that established by the reverse process of reducing iron oxid by 
hydrogen. 

Chemical equilibrium is the state of rest caused by the mutual 
check of two opposing reactions. Such a limit obtains in all 
chemical processes, although in many the balanced concentrations 
of some of the substances engaged are so small as not to be noticed, 



WATER 



83 



the observer detecting the movement in one direction only (pp. 37, 
43, and 134). 

The usual terms employed to describe a chemical reaction are 
based upon the theory of an impelling force causing one element 
to drive another out. It is more satisfactory to discover the posi- 
tion of equilibrium by calculating the ratios of chemical forces 
and then state them as relative velocities. When the velocities of 
two opposite reactions are equal, so that in a unit of time each acts 
as much as the other, we have the condition of equilibrium. In the 
diagram (Fig. 30) it is shown that the point of equilibrium may be 






Maltose changing to Formation of ethyl Reduction of Fe30 4 . 

glucose. acetate. 

Fig. 30. — Equilibrium of opposing reactions; the vigor is indicated by the height of the lines D and F, 
and the velocities by the arrows. 

attained at different degrees of concentration of the materials, 
dependent on the initial vigor of the two reactions. 

The velocities are indicated by the length of the arrow's. The 
balls rolling down the inclines show T at E, the point of rest when 
chemical change ceases, leaving some of the original material 
present with the new products. In b is showm acetic acid acting 
on ethyl alcohol at D, producing ethyl acetate and w T ater at F 
(P- 433)- The change ceases when 67 per cent, of the material 
has been transformed. The ester formation is represented by the 
motion along DE; the reverse hydrolysis by FE. 



WATER 

Formula H 2 0. Molecular weight, 18. 

Occurrence. — In nature it exists as a solid in snow and ice; as 
a liquid it forms lakes, rivers, and seas; suspended in the air as 
minute liquid particles it forms the clouds and fog; as a colorless 
gas it is a constituent of the atmosphere. It comprises three- 
fourths or four-fifths of the substance of plants and animals, and 
is found in molecular union in various minerals, as water of crys- 
tallization, where it is indicated by the plus sign or comma before 
H 2 0, as in the formula for sodium carbonate: Na 2 C0 3 + ioH 2 0. 
The water thus combined in crystals is in definite proportions, is 
always necessary to their form, and often to their color, but does 
not affect their chemical relations. A crystal which, like sodium 
carbonate, gives off this water spontaneously is said to effloresce. 



8 4 



NON-METALS 



Salts which, like calcium chlorid, absorb water from the air 
and dissolve are said to deliquesce. 

Formation. — It has been stated before that by electrolysis of 
water two volumes of hydrogen are evolved at the negative elec- 
trode and one volume of oxygen at the positive. If these three 
volumes be introduced into an eudiometer 1 (Fig. 31), they will 
explode by a spark and unite to form two volumes of the vapor 
of water when measured at 100 ° C. (21 2 ° F.). 

Water is formed when any compound containing hydrogen is 
burned in oxygen or air. 




A B C 

Fig. 31. — A, Battery; B, electrolytic cell; C, mixed gases, explosive. 



Physical Properties. — Without taste or odor, water appears 
colorless in ordinary vessels, but it is bluish green when observed 
in layers several yards in thickness. Its freezing-point is o° C. 
(32 F.), its boiling-point ioo° C. (212 F.). It is a poor con- 
ductor of heat, but may be heated readily in masses from below 
through the circulation of convection currents. It contracts when 
cooled until the temperature is lowered to 4 C. (39.2 ° F.), at 
which point it reaches its maximum density. This property is the 
opposite of that possessed by most substances, where the with- 
drawal of heat means contraction indefinitely. From 4 C. 
(39 F.) down to o° C. (32 ° F.) water expands as it cools (one 
volume becoming 1 +0.00012). In freezing as ice it becomes 
specifically lighter and floats on the liquid water. This explains 
the fortunate circumstance that lakes, rivers, and seas in cold 
latitudes do not freeze solid from the bottom up. Under the 
surface-ice the water keeps at a temperature compatible with the 
life of the aquatic inhabitants. Winds cool the surface-water, 
which, becoming heavier, sinks, and lighter and warmer water 
rises to its place. This goes on until the whole is reduced to 4 C. 
(39.2 ° F.), and then the surface-water no longer sinks. Ice is 

1 An eudiometer is an instrument for analyzing gases by exploding out the hydro- 
gen with oxygen, or vice versa, and measuring the calm gases left. 



WATER 85 

formed only at the top, the mass of water retaining a temperature 
of 4 C. (39-2° F.). If water became heavier as it cooled down 
to the freezing-point, a continual circulation would be kept up 
until the mass was cooled to o° C. (32 ° F.), when solidification of 
the whole would take place. 

Most of the soluble solids dissolve in water. Being neutral, 
it takes on the properties of dissolved substances in odor, color, 
taste, or chemical reaction, acting simply as a vehicle. Natural 
waters vary in the character and amount of these constituents 
because of the difference in the rocks and soils from which they 
have been extracted. Beyond a certain proportion the minerals 
give it an unwholesome quality, and then the water is not con- 
sidered potable, but is called a mineral water. If it be highly 
charged with gases, it is said to be effervescent. Sulphur water 
contains the gas hydrogen sulphid. Chalybeate waters have iron 
salts in solution (p. 256). 

Natural water is never chemically pure: even in the cloud or 
rain-drop it has taken up gases or dust from the atmosphere. By 
the term aqua (U. S. P.) is meant the purest attainable in a natural 
state. To get it free from impurity it must be distilled. 

Distillation. — It is first changed into steam by heat and then 
the steam is cooled again until it condenses to liquid water. The 
impurities that are not volatile are left behind. The operation 
may be conducted in the condenser shown in Fig. 77. A current 
of cold water circulates in an outer jacket around an inner tube 
for steam. The hot vapor flowing down loses its heat to the cold 
water streaming up, which absorbs it, the two opposing currents 
tending to an equilibrium of temperature. 

Sublimation. — When the distilled substance is a crude solid 
like native "brimstone," which is recovered as a purified solid 
like sulphur, the substance vaporized by heat is temporarily 
dissolved in the air and is said to be sublimed. 

Aqua destillata (U. S. P.) is prepared by distilling 1000 parts 
of water, throwing away the first condensation of 100 parts as 
likely to contain dissolved gases such as ammonia; saving the 
next 800 parts, and leaving the last 100 parts in the retort lest 
the thickened fluid in boiling should spray over its salts. 

Atmospheric Water. — Beside the visible forms of cloud or 
fog, the moisture of the air exists as an invisible vapor. The 
actual presence and amount of this water may be shown by sending 
the measured air through a drying tube containing calcium chlorid; 
the salt grows moist and increases in weight. A given volume 
of air is found to hold amounts of water vapor varying with the 
pressure and temperature. While some moisture is always pres- 
ent, it rarely happens that the air is saturated, commonly the 



86 



NON-METALS 



I 



moisture present reaching only from 50 to 70 per cent, of the 

maximum. 

By cooling the air sufficiently a temperature is reached at 

which the aqueous vapor has the pressure of its saturation-point. 

The slightest decline now causes the vapor to condense as dew. 

This temperature is known as the dew-point. A hygrometer is 
an instrument constructed to determine the 
amount of moisture in the air. The one com- 
monly used consists of two thermometers, one 
dry, while around the bulb of the other is 
wrapped a cotton wick kept wet by one end 
dipping in a vessel of water. The wet bulb, 
by evaporation, indicates a lower temperature 
than the dry-bulb instrument. The rate of 
evaporation is the cause of the difference, and 
this depends on the amount of moist vapor and 
the temperature. If the difference between the 
instruments be great the air is dry, if slight the 
air is moist. By means of tables these fac- 
tors can be converted into relative humidity. 

Relative humidity is a term applied to this 
fraction of full saturation for the air at existing 
temperature and pressure. Relative humidity 
of 100 means that the air is saturated, and 

that water will be precipitated should the temperature of pressure 

decline. An increase of temperature or pressure would raise the 

capacity of the air as a solvent, and the relative humidity would 

fall. Less than 50 per cent, makes the air dry; with more than 

70 per cent, it is humid and depressing. 

HYDROGEN DIOXID OR PEROXID 

Formula, H 2 2 . Molecular weight, 34. Specific gravity, 1.455. 

A trace of hydrogen dioxid is found in saliva, in the air, in snow, 
and in rain-water. 

Preparation. — Dilute mineral acids acting on barium dioxid 
will produce hydrogen peroxid mixed with water. 



Fig. 32. — Wet- and dry- 
bulb hygrometer. 



Ba0 2 + H 2 S0 4 =• BaS0 4 + H 2 2 

Barium dioxid. Sulphuric acid. Barium sulphate. Hydrogen dioxid. 

It is evolved at the same time with the ozone when moistened 
phosphorus slowly oxidizes. 



H,0 



+ 



2O, 



O, 



'3 
Ozone. 



+ 



H,0, 



HYDROGEN DIOXID OR PEROXID 87 

In a concentrated form for use as a bleaching agent it is 
obtained by the action of dilute acids on sodium peroxid. 

Na 2 2 + 2HCI = 2 NaCl + H 2 2 . 

Sodium peroxid. Hydrochloric acid. Sodium chlorid. 

Water becomes a source in dissolving sodium peroxid. 
2H 2 + Na 2 2 = 2NaHO + H 2 2 . 

Properties. — When pure hydrogen peroxid is a syrupy liquid 
without color or odor, but with a metallic taste, and having a ting- 
ling effect on the mouth. It is soluble in water, alcohol, and 
ether in all proportion. The pure form decomposes readily into 
water and oxygen at ordinary temperatures, more rapidly at 
higher temperatures. Practically it is oxidized water. 

H 2 2 = H 2 + O. 

It may give off 475 volumes of oxygen, while the ordinary 
dilute form yields about 10 volumes. When diluted and slightly 
acidulated it is much more stable and may be concentrated to an 
extreme degree by careful evaporation under 60 ° C. (140 ° F.) 
without decomposition. 

Catalytic Reactions. — When concentrated hydrogen dioxid 
comes in contact with certain metals, as platinum or certain oxids, 
as manganese dioxid, it breaks up explosively into water and 
oxygen. A piece of spongy platinum, when immersed in dilute 
hydrogen dioxid, becomes enveloped in a layer of oxygen gas. 
Removing this layer of oxygen another layer forms, and so on, 
until the dioxid is to a great degree decomposed, the platinum 
remaining unaffected. 

Catalysis is chemical action as affected by the presence of a 
substance which does not itself enter into the reaction. A cat- 
alyzer is a body which, without appearing as an end-product in 
a chemical reaction, alters its velocity. While in most cases the 
catalyzer hastens the change, it is probable that some bodies, like 
hydrocyanic acid, inhibit action, and hence may be called ''retard- 
ing catalyzers." The agent usually appears to act much as a lub- 
ricant does on machinery — that is, it accelerates a movement which 
would otherwise occur much more slowly if at all, the lubricant 
itself not being consumed in the process. 

The Energy of Hydrogen Dioxid. — To decompose water, 
H 2 (a stable substance), it requires a strong electric current or 
very high temperature. Hydrogen dioxid, H 2 2 , with its addi- 
tional atom of oxygen, acquires instability in a high degree. In 



88 NON-METALS 

giving up that oxygen a large amount of heat is liberated. Each 
molecule of the dioxid holds that much more intrinsic energy than 
the molecule of water to which it is converted. This intrinsic 
energy gives it high instability and chemical activity in proportion. 

Aqua hydrogenii dioxidi, U. S. P. (oxygenated water) is a solu- 
tion in water of about 3 per cent, by weight of the dioxid correspond- 
ing to about 10 volumes of available oxygen. Without color or 
odor, it has a peculiar, feebly acid taste, due to a trace of sulphuric 
acid. Mixed with saliva it evolves oxygen, as it also does when 
mixed with pus. 

To prevent spontaneous deterioration and explosive expulsion 
of the stopper it is often kept uncorked in a refrigerator. By 
means of glycerin a more stable solution is prepared. A solution 
in ether is called ozonic ether. 

Uses in the Arts. — As an oxidizing agent it has quite remark- 
able bleaching powers, which are employed in bleaching hair, 
ostrich feathers, and wool. Books and engravings stained by 
mould and time are safely cleaned by it. 

Uses in Medicine. — It is an antiseptic, destroying bacteria; 
a deodorant, decomposing hydrogen sulphid; and a styptic, coagu- 
lating the blood. It is of great service as a topic application to 
the throat in scarlatina and diphtheria, or as a disinfectant lotion 
for abscesses and wounds. When internally administered in doses 
of f3j-iv, well diluted, care should be taken that the solution be 
free from barium and hydrofluoric acid. The small amount of 
free acid, if present, may be neutralized with a sufficient amount 
of sodium bicarbonate. It is given by the mouth as an antidote 
to the cyanids, phosphorus, and the alkaloids. 1 

With hydrocyanic acid it forms oxamid; hence, if potassium 
cyanid has been taken, a tablespoonful of vinegar must be added 
to liberate the acid from the cyanid. 

2HCN + H 2 2 = C 2 2 N 2 H 4 

Hydrocyanic acid. Oxamid. 

Not only is the stomach flushed with the dioxid diluted, but 
15 m. of the official preparation are also injected subcutaneously 
every ten minutes until respiration improves. 

Incompatibles. — To arsenic and the sulphids, hydrogen 
peroxid supplies oxygen, but it reduces many compounds, like 

1 Solutions of potassium permanganate and hydrogen dioxid when mixed, recip- 
rocally promote their yield of oxygen. The official 3 per cent. H 2 2 , about 35 cc. 
diluted with a liter of water, when mixed with a solution of potassium permanganate, 
2 gm. in 5 cc. of diluted acetic acid to a liter of water, produces at once energetic 
disengagement of oxygen. They should be kept separate until needed and brought 
into contact only at the site of the disease; as antidotes, the above dioxid solution 
should be given in doses of a tablespoonful first and followed each time by an 
equal amount of the permanganate. 



SOLUTION 89 

manganese dioxid, silver oxid, and potassium iodid. Many sub- 
stances in a state of fine division, acting by catalysis, cause hydrogen 
dioxid to lose its oxygen. Among such substances are included 
all the ferments or enzymes, ordinary dust, powdered charcoal, 
fibrin, platinum, and gold. Hydrogen dioxid is also decomposed 
by albumin, ammonia, iodids, chlorids, bromids, chlorin-water, 
solution of chlorinated soda, carbolic acid, ferric salts, hydrocyanic 
acid, lime-water, the permanganates, and alcoholic tinctures. 

Tests. — (1) Starch and Iodids. — A few drops of a solution of 
potassium or cadmium iodid are added to a cold solution of starch 
acidulated with acetic or citric acid. Then the fluid to be tested 
is added. Hydrogen dioxid, even in the presence of ferrous 
sulphate, produces a blue color, liberating free iodin, which unites 
with the starch. Other oxidizing agents liberate iodin, but not 
in the presence of ferrous sulphate. 

2KI + H 2 2 = 2KOH + I 2 . 

This test will show hydrogen dioxid when there is present 
only 0.05 mgm. per liter. 

(2) Perchromic Acid. — When acidulated with dilute sulphuric 
acid, hydrogen dioxid will cause potassium dichromate to form 
blue perchromic acid — 4.Cr0 3 . By shaking with ether and setting 
aside, the product separates as a supernatant transient violet- 
blue layer. No other substance oxidizes chromic to perchromic 
acid. 



SOLUTION. DIFFUSION. DIALYSIS. OSMOSIS 

SOLUTION 

Some solids when immersed in water disappear in it, imparting 
to the liquid their own properties, such as color, odor, and taste. 
They assume for the time being the liquid state. A solution of 
sugar is sweet, and of salt brackish, the chemical behavior being 
that of the original solid. The particles of the solid are diffused 
so evenly in the solvent that every part of the liquid contains equal 
amounts dissolved in it. One grain of fluorescin or uranin will 
render fluorescent or will color one hundred million grains of 
water. The original grain has been divided infinitely in the 
process of absorption by water. 

Solutions are homogeneous mixtures of two or more elements 
or compounds which cannot be separated mechanically. 



9° NON-METALS 

Solutions of Solids in Liquids. — It is a general rule that 
some portion of a solid, albeit infinitesimal, always dissolves in 
a liquid in contact with it. A trace of platinum dissolves in water. 
This is not the only form of solution, but being the most familiar, 
the word solution is taken to mean the solution of a solid in a 
liquid. Although it is not a chemical effect, there is a limit to 
the amount of any solid dissolvable in a Certain amount of any 
liquid. This limit depends upon the nature of the solvent, the 
nature of the substance, and the temperature. 

As more substances are freely soluble in water than in any other 
liquid, we speak of the solubility of a substance without naming 
the solvent, meaning water. Water, however, is not a good 
solvent for a large number of solids — like the resins, which dissolve 
freely in alcohol; phosphorus, soluble in ether; sulphur, soluble 
in carbon bisulphid; and gutta-percha, soluble in chloroform. 
While theoretically all solids are said to be soluble in water, to 
some degree discoverable by physical tests, the amount of gold and 
other metals, quartz and many other minerals, is so small as not 
to be discovered by chemical tests. These substances are con- 
sidered to.be practically insoluble, while the contrary is the case 
with many metallic salts, acids, alkalies, sugars, and a host of 
organic products. The solubility of some of these is very great, 
yet in the extremest case there is a limit beyond which it is not 
possible to dissolve a solid in a liquid. This limit, constant at 
any given temperature, is the point oj saturation. The solution 
is said to be saturated. In making a saturated solution it will be 
found a great help to have the solid pulverized and stirred or 
shaken with the solvent. Practically this method is not so rapid 
as one based upon the fact that solubility of most substances 
rises with the temperature. Thus, at o° C. (3 2° F.), 100 parts 
of water dissolve 26 parts of magnesium sulphate; at 40 ° C. 
(104 F.), 45 parts; at ioo° C. (212 ° F.), 74 parts. Among 
the few exceptions the calcium salts and the cyanids may be 
taken as examples. 

After having made a saturated solution of a calcium salt at 
ordinary temperatures, if heat be applied, the effect is the pre- 
cipitation of the salt. Common salt is almost equally soluble at 
all temperatures. With the great majority of solids, such as sugar 
and alum, if hot water be used to make the solution and a large 
quantity of the solid be shaken with it, when the solution cools the 
excess dissolved at the higher temperature will be thrown out and 
a saturated solution be left. Sometimes the clear liquid may be 
cooled without throwing out all excess. Thus we may get a 
solution which at any given temperature holds more of the solid 
than a simple saturated solution. The equilibrium is not stable 



SOLUTION 91 

because agitation with a crystal of the undissolved substance 
will cause the excess of the solid in solution to be deposited. 
The supersaturated solution is thus converted into a saturated 
one. 

If sodium sulphate be dissolved by aid of heat and the clear 
liquid free from undissolved particles be allowed to cool quietly, 
excluding dust, a crystal of the same salt dropped into the super- 
saturated solution causes immediate crystallization with elevation 
of temperature. 

While the dissolved substance can not be separated by mechan- 
ical means, it may by evaporation of the liquid. The solid is not 
carried over in the vapor, but is recovered unchanged. 

Solutions of Gases in Liquids.— All liquids possess the 
power (though it may be infinitely small) of absorbing all gases. 
The amount absorbed varies with the nature of the liquid, the 
nature of the gas, the temperature of the solvent, and the pressure 
on the gas. At o°C. (32 ° F.) a liter of water dissolves only half 
as much carbon dioxid as an equal volume of alcohol. 

It has been previously stated that oxygen, hydrogen, nitrogen, 
and air are soluble in water to a slight extent only. We shall 
learn that chlorin and hydrogen sulphid are more soluble, while 
hydrochloric acid and ammonia are absorbed by water in large 
amounts. 

The extent of solubility is much influenced by temperature 
and pressure. As the temperature rises the amount of gas dis-. 
solved decreases. At 10 ° C. (50 ° F.) 100 volumes of water will 
hold in solution no volumes of nitrous oxid; when heated to 
20° C. (68° F.) much gas escapes, leaving only 67 volumes. 

The relation of pressure to solubility is expressed in Henry'' s 
law: The amount oj a gas absorbed by a liquid is directly propor- 
tional to the pressure to which the gas is subjected. Thus, under 
a pressure of five atmospheres, water dissolves five times as much 
carbon dioxid as under a pressure of one atmosphere. 

Solutions of Liquids in Liquids. — These belong to one of 
two classes: first, where the liquids mix in all proportions homo- 
geneously, as alcohol and water; second, where they dissolve in 
each other to a limited extent only, as ether and water. Theoret- 
ically, all liquids are soluble in each other to at least an infini- 
tesimal degree, but, practically, there are liquids which are not 
miscible, such as oil and water. 

When liquids are freely miscible, the mixture often has 
properties representing the sum of those of the components, though 
they are never strictly additive. In most cases there is a change 
of volume; usually the mixture shrinks, but sometimes it increases. 
In most cases there is a change of temperature which may be 



92 NON-METALS 

either a rise or a fall. When alcohol is mixed with water a con- 
traction of volume occurs and the temperature of the mixture rises. 

When liquids are miscible to a limited extent only, the 
properties of the mixture can not be assumed to be the sum of the 
constituents. When there is an excess of one liquid and a mechan- 
ical separation, it will be found that each separate liquid has 
dissolved a different amount of the other. If equal volumes of 
ether and water be shaken together and set aside, they will soon 
form two layers. The upper layer of ether contains 2 per cent, of 
dissolved water; the lower layer consists of water holding 10 per 
cent, of the ether dissolved in it. It can be stated that the mutual 
solubility is limited only at ordinary temperatures. By heating, 
the liquids will at last reach a point where they become miscible 
in all proportions. 

Solutions of Gases in Gases.— When two gases in contact 
do not unite chemically, they diffuse into one another, making 
a uniform mixture, as the nitrogen and oxygen of the air. There 
is no limit to the capacity of a gas to dissolve another, the result- 
ing mixture having the combined properties of the components. 
The pressure of the mixture equals the sum of the pressures of 
the constituents (see p. 41). 

Solutions of Liquids in Gases.— Generally speaking, liquids, 
will evaporate into surrounding gases. The gas dissolves the 
liquid with such freedom that the vapor-pressure of the evap- 
orated liquid is the same as it would be in a vacuum (see p. 39). 

Solutions of Solids in Gases. — Certain solids, such as iodin,, 
without being first liquefied, pass into the state of vapor and dis- 
solve in the air or other gases. The solubility increases with rise 
of temperature. 

DIFFUSION 

Diffusion of Gases. — In the section that treats of hydrogen 
(page 81) it was shown that a gas passes through the porous walls, 
of a cell much faster than the air passes out. If the experiment 
be repeated with air outside and carbon dioxid inside, a similar 
effect is produced, the lighter gas diffusing more rapidly than the 
heavier. 

Graham's law states that the velocities of diffusion of any two 
gases are inversely as the square roots of their densities. Oxygen 
weighing 16 diffuses one-fourth as fast as hydrogen weighing 1.; 
chlorin weighing 36 diffuses at one-sixth the rate of hydrogen. 
This follows from the kinetic theory of gases, which assumes that 
the mean velocities of the molecules of gases are inversely propor- 
tional to the square roots of their densities. 

Diffusion of Liquids. — If a cylindric vessel be partly filled 
with water and the water underlaid with a colored solution (a sat- 



DIALYSIS 93 

mated solution of copper sulphate), by pouring the latter solution 
through a long funnel reaching to the bottom of the vessel two 
well-defined layers will be formed. If the cylinder be set aside 
for a few days it will be seen that the blue color has risen gradually 
and extended into very part of the water, making a uniform 
tint throughout. Chemical analysis will prove that the copper 
salt has distributed itself equally throughout the solvent, making 
a homogeneous solution. Therefore, two solutions of different 
substances will diffuse into each other until there is but one homo- 
geneous mass. Moreover, regardless of the weight of the dissolved 
substance, the solution maintains this property of uniform distri- 
bution indefinitely. The force of diffusion overcomes the counter- 
acting force of gravity. 

From an extended series of experiments Graham deduced the 
following conclusions: The quantities of a dissolved salt which 
diffuse in equal times are proportional to the concentration of the 
solution, and to the rise in temperature. 

Different substances have different rates of diffusion, cane- 
sugar diffusing with seven times the velocity of albumin. Iso- 
morphous salts frequently show equal rapidity. A double salt, 
such as alum, may be resolved into its components by means of 
their unequal velocity, the more diffusible part moving away at 
a greater rate. 

DIALYSIS 

If a drum of glass open at both ends be closed at one end with 
a stretched membrane, such as bladder or parchment, then floated 
on water, and a mixture of substances, such as sugar and albumin, 
placed in it, a remarkable separation of 
the sugar and albumin occurs. The sugar 
passes out through the membrane, while 
the albumin remains behind. 

This process of separation is known as 
dialysis, the instrument is a dialyzer. The 
sugar is the diffusate, the albumin, the dial- 
ysate. Graham divided all substances into 
two classes: crystalloids, those which dif- FlG & 3 ^&tof SgS *" 
fuse and are also crystallizable ; colloids, 

those which are unable to pass through the membrane and which 
are also amorphous, like gum or glue. To the class of crystal- 
loids belong sugar, the mineral salts, and acids; to the colloids 
belong albumin, gelatin, starch, and gum. Crystalloids have 
molecules sufficiently small to pass where the larger molecules 
of the colloid can not readily move. In some cases relatively 
small molecules appear to cling together to form solution aggre- 
gates which can not diffuse. Some of the metals — platinum, gold, 




94 



NON-METALS 



and silver — can be obtained in a condition known as colloid solu- 
tion. A strong electric current is sent through water by platinum 
electrodes with tips close enough to make an electric arc. Minute 
particles of platinum are torn off in aggregates, making a brown 
solution which does not dialyze, and hence is called colloidal. 
Viewed by the ultramicroscope, the " solution" proves to be a sus- 
pension of shining metallic particles. Such a solution has the 
catalytic power of a ferment on sugar and fat (p. 536). 



OSMOSIS 

If a dialyzer full of molasses or brine be immersed in water it will 
be noticed that the contents of the inner vessel increase and the mem- 
brane appears to be forced up. If instead of a cylindric drum a 
long-stem funnel be used (Fig. 34), stretching the parchment over 

the head of the funnel, b-a, we 
have an osmometer, or apparatus 
for observing the phenomenon 
of the transmission of liquids, 
which causes the level of 
the fluid to rise as in tube 
n. We have seen that the pas- 
sage of a dissolved substance 
is called dialysis; when the 
passing molecules are those 
of the water it is termed os- 
mosis. There is in reality an 
interchange, but more mole- 
cules of water stream into the 
brine than of salt out to the 
water. 

A better medium for show- 
ing this pressure of the water 
toward a solution of salts is 
the semipermeable membrane 
0} Pfeffer, made by precipita- 
ting gelatinous copper ferro- 
cyanid within the pores of 
a membrane or the walls of 
a porous cell. This is per- 
meable to the water, but not 
to the dissolved substance; it 
is not a dialyzer. When a 
solution of cane-sugar is put inside of an osmometer with this arti- 
ficial membrane separating it from water, the osmotic current is. 




Fig. 34 



-Endosmometer: a—b, porous membrane; 
v, diffusate risen to n. 



osmosis 95 

toward the sugar, v, no sugar passing out. In their futile efforts 
to diffuse out toward the water the sugar molecules exert a pres- 
sure which is toward all the boundaries of the cell, including the 
free surface of liquid in the tube n. The free surface of any 
liquid is a film or layer with peculiar powers. Pressure upward 
upon it causes it to act as a piston head. 

It moves upward, enlarging the volume of fluid in the cell, making 
easier the entrance of water through the membrane. This pressure 
causes the level of water in the stem to rise to a certain point, when 
the pressure reaches an equilibrium with the weight of the column 
of fluid. This highest degree of pressure is known as the osmotic 
pressure of the solution. If the semipermeable cell be filled with 
a normal solution of cane-sugar, and the stem be a capillary- tube, 
pure water will press in so fast that the liquid in the tube rises more 
than a foot an hour, and in a day will reach a pressure of thirty feet 
of sugar solution. By connecting to the cell a tube of the form 
used for manometers we can calculate the pressure in exact terms. 

Experiments show that the osmotic pressure of a solution is 
governed by the following laws: * 

(i) At a constant temperature the osmotic pressure is pro- 
portional to the concentration. 

(2) With a given solution it is proportional to the absolute tem- 
perature. 

(3) Under constant conditions of concentration and tempera- 
ture different substances in solution exert different pressures. 

(4) The molecular weights in grams per liter of different sub- 
stances exert the same pressure at the same temperature. 

These laws resemble closely those stated as governing the 
pressure of gases in confined spaces (see p. 40). The osmotic 
pressure, like the gas pressure, varies with the concentration, and 
increases gT¥ f° r every rise of i° C, or 4^ for every i°F. 

According to the law oj Avogadro, equal volumes of all gases 
at the same temperature and pressure contain the same number 
of molecules. So in equal volumes of solutions having the same 
osmotic pressure there are the same number of molecules. The 
osmotic pressure of a solution of cane-sugar is exactly equal to 
the gas pressure of a gas with the same number of molecules in 
a given volume. The gas pressure exerted by a gas molecule 
equals the osmotic pressure of a dissolved molecule. These laws 
do not apply to the osmotic pressures of most salts, all the strong 
acids, and all the strong bases, which are always greater than the 
laws would lead us to expect. 

To solve the problem presented by so many exceptions, the 
theory of ionization or electrolytic dissociation is needed. If the 
acids, bases, and salts exert abnormal osmotic pressure they must 



96 NON-METALS 

have more dissolved particles than can be accounted for by their 
molecules. Let us suppose that the theory given (p. 52) to explain 
electrolysis be true — that is, that in making solutions of salts, acids, 
and bases there is a partial breaking up of the molecules, not into 
free atoms, but into electrically charged parts called ions, which 
may be charged atoms or charged groups. In this way we can 
conceive of more particles than are accounted for by the molecules. 
According to the method of Arrhenius the percentage of molecules 
broken down into ions can be calculated. When this is done, 
there is found the right proportion of particles, i. e., molecules plus 
ions, to bring the exceptional substances under the reign of the 
laws above stated. 

There are so many experimental difficulties in the way of cal- 
culating the absolute osmotic pressures of concentrated solutions 
that for convenience dependence is placed upon the mathematic 
relations known to exist between osmotic pressure and certain 
other properties easily measured. For instance, solutions of equal 
osmotic pressure have also the same freezing-point. In the section 
dealing with the Freezing-point (pp. 38 an d 368) it was stated that 
depression in a solution is proportional to the number of particles 
dissolved. The amount of freezing-point lowering of any normal 
(gram-molecular) solution in water has been stated to be the 
constant 1.87. (p. 38). 

Therefore, the osmotic pressure of a solution can be calculated 
by dividing 1.87 into the amount of lowering of the freezing-point 
of that solution in Centigrade degrees (its A — delta). Blood- 
serum freezes 0.56 ° C. below the freezing-point of pure water. 
0.56 C. divided by 1.87 gives 0.3. Now the constant osmotic 
pressure for normal solutions of undissociated substances is 22 
atmospheres; therefore, 22 multiplied by 0.3 gives 6.6 atmospheres 
as the osmotic pressure of blood-serum. A solution of a salt 
having the same osmotic pressure as blood-serum is said to be 
isotonic or isosmotic, such as 0.95 per cent, sodium chlorid. A 
solution of higher pressure is said to be hypertonic; one of lower, 
hypotonic. 

The physiologic solution of common salt is made a little less 
than this strength, 7 to 9 grams per liter (332 gr. to 1 quart), so 
that when injected by hypodermoclysis it will diffuse as freely as 
blood-serum itself. The laws of osmotic pressure have been 
a great help to physiologists in solving the problems of secretion 
and absorption. 



NITROGEN 97 

NITROGEN AND THE ARGON GROUP 

NITROGEN (A*ote) 

Symbol, N. Atomic weight, 14.04. 

Occurrence. — Free nitrogen constitutes four-fifths of the vol- 
ume of the air, which also contains a trace of it combined, as 
ammonia (NH 3 ). It is found in combination in nitrates and 
many animal and vegetable substances. 

Preparation. — To obtain nitrogen from the air, the oxygen 
must be removed. A piece of phosphorus as large as a pea is 
floated on a cork in a basin of water, ignited, and covered with 
a bell-jar. The phosphorus combines with the oxygen, forming 
clouds of phosphorus pentoxid which are obsorbed by the water. 
Left in the jar is the nitrogen, containing a trace of C0 2 and of 
argon. Nitrogen can be obtained more pure by not igniting the 
phosphorus, but by allowing it to oxidize slowly. It can also be 
prepared by heating a strong solution of ammonium nitrite or a 
mixture of ammonium chlorid and potassium nitrite. 

Properties. — Nitrogen is a colorless, tasteless, inodorous gas, 
with a specific gravity 0.9701. At — 130 C. ( — 202° F.), under 
280 atmospheres, it is condensed into a colorless liquid. It will 
not support combustion, nor will it burn. It is not poisonous, for 
if so the air would kill. All animals die in the pure gas, owing 
to the absence of the life-sustaining oxygen. 

Because it does not combine under ordinary circumstances with 
any common substances it has been regarded as the type of pas- 
sivity, but this can be said more properly of argon, which is asso- 
ciated with the nitrogen in the air. The nitrogen of the air is 
made available for use through union with its associate oxygen 
only by the expenditure of much energy, which is stored up for 
later work on the decomposition of the resulting compound. 
Flashes of lightning in nature and powerful electric discharges in 
a suitable apparatus compel this union. The living energy in 
the nitrifying bacteria at the roots of pod-bearing plants causes 
a combination of the two in the nitrates of the soil, v which give it 
fertility. For the growth of crops dependence is largely placed 
upon animal manures, in the evil-smelling components of which is 
combined nitrogen with a working capacity too valuable to be 
wasted. Having been assimilated by the plant, the combined 
nitrogen is taken up by the animal in the proteins of food, the 
nitrogen circulating through both in various forms, but always in 
some compound essential to life. Nitrogen forms compounds 
very slowly, and most of them decompose with great readiness, 
some of them explosively, giving back the energy consumed in 
7 



9 8 NON-METALS 

causing their union; namely, gunpowder, nitroglycerin, nitro- 
cellulose, or gun-cotton. Nitrogen imparts an energetic quality 
to prussic acid, HCN; to nitric acid, HNO s ; to ammonia, NH 3 ; 
to powerful alkaloids, and the albuminous principles. These 
compounds of nitrogen are considered in other places. 

Argon and Its Congeners. — Until recently the inert con- 
stituent of the air was considered to be nitrogen only. About one 
part of the 80 per cent, of so-called nitrogen in the air has been 
proved to consist of argon and its congeners, distinguished by the 
fact that they show no evidence of chemical attraction, forming no 
compounds. 

Argon (A = 40) was first discovered in 1894 by removing from 
a measured portion of air first its oxygen, by means of phos- 
phorus or heated copper, and then its nitrogen, by means of red- 
hot magnesium, by which N is absorbed. By weight it forms 
1.2 per cent, of the air, which ratio is constant. 

Properties.— Argon is a colorless, odorless, and tasteless gas 
having a specific gravity 19.941. It is soluble in the proportion 
of 4 parts to 100 of water, and it solidifies under cold and pressure. 
It has a peculiar spectrum. The chemical inactivity makes it 
a difficult matter to determine its combining weight, but by physical 
analogies the conclusion has been reached that it is 40. 

Helium (He = 4). — This is a very light gas, with the proper- 
ties of argon. It was first suspected to be an unknown element 
of the sun's atmosphere, causing a strong line in the yellow-green 
of the solar spectrum. The same line has been found, and also 
those due to argon in the gases evolved on ignition of certain 
minerals. By cooling these gases to extremely low temperatures 
they are condensed to a liquid. If the temperature be permitted 
to rise, the helium becomes a gas first, leaving the argon a liquid. 
In air, by its evaporation from the liquid state, helium and three 
other gases with characteristic spectra and different densities have 
been discovered in amounts as follows: helium, 1 in 1,000,000; 
neon (Ne=2o), 1 in 100,000; krypton (Kr = 82), 1 in 1,000,000; 
and xenon (X=i28), 1 in 20,000,000. 



CARBON AND ITS OXIDS 

CARBON 

Symbol, C. Atomic weight, 12. 

Occurrence. — Free carbon exists in nature in three allotropic 
forms: as uncrystalline or amorphous carbon; graphite, either 
amorphous or imperfectly crystalline; and as diamond, in octa- 



CARBON 



99 



hedral crystals. In the air it exists in combination as carbon 
dioxid. It occurs widely distributed in the mineral kingdom in 
carbonates, and it is a constituent of all organic substances, being 
more necessary to the vital processes than any other element. 

Properties. — All forms of carbon have the following proper- 
ties in common: They are solid, tasteless, odorless, and except at 
very high temperatures, insoluble, infusible, and non-volatile. 

Diamond is almost pure carbon; usually being transparent 
and colorless, though colored specimens are not rare. Particles 
of carbon in molten iron change to small crystals of diamond by 
the heat and the pressure of the metal as it contracts on cooling. It 
is cut into many facets at certain angles, so as to enhance the luster 
due to its high dispersive and refractive power. As the hardest 
substance known, it is cut only by its own dust. It has a specific 
gravity 3.55. It is a non-conductor of electricity and a poor con- 
ductor of heat. Resisting all lower temperatures, under the heat 
of the electric arc, in a vacuum, it is converted into graphite; in 
the air it burns to carbon dioxid. 

Graphite or plumbago is a bluish-black, friable substance 
with a metallic luster, but having a greasy feeling and leaving 
a line when drawn across paper, hence called black lead. It is 
the "lead" in the common lead-pencil. Its specific gravity is 2.18; 
its crystals are six-sided plates. The charcoal filaments of the 
Edison electric lamp in time change by heat to graphite. A good 
conductor of heat and electricity, it burns at a high heat to carbon 
dioxid. 

Amorphous Carbon. — The purest is lamp-black, the soot 
of burning resins or oils. Other forms less pure are wood char- 
coal, animal charcoal, mineral coal, and coke. All of these are 
endowed with great energy, convertible into heat, light, electricity, 
or mechanical motion. When burned in air the end-product is car- 
bon dioxid. 

Anthracite and bituminous coal are of vegetable origin. 
The plants of the carboniferous period of geologic history were 
transformed into coal by decay, heat, and pressure. Coke is the 
charcoal of bituminous coal. Gas carbon is a form of coke found 
in gas retorts and molded to make electric battery carbons and 
arc lights. 

Wood charcoal is used in medicine under the official name 
carbo ligni. Charred bone, or bone-black, called carbo animalis, 
contains the mineral ash as an impurity. When washed with 
hydrochloric acid the ash is dissolved out and there is left carbo 
animalis pnrificatus, U. S. P. 

Uses. — In therapeutics charcoal is valued because it has the 
power of absorbing foul gases and active oxygen in large volumes. 



ICO 



NON-METALS 



Water having an odor is made sweet, and coloring-matters are 
removed from various liquids by nitration through charcoal. 
Applied as a poultice to foul ulcers it not only deodorizes them, 
but, from the NH 3 and H 2 S, by promoting their oxidation, forms 
acids which destroy and hasten the removal of sloughs. 

In the chemical laboratory charcoal is used as a reducing agent. 
Heated to redness it not only takes oxygen from the air to form 
carbon oxids, but also from metallic oxids, reducing the latter to 
the metallic state. For this property of extracting metals it is 
heated with ores in furnaces. 

Compounds. — Carbon unites with oxygen, hydrogen, nitro- 
gen, and sulphur to form the very large number of compounds 
considered in the section of this work entitled Organic Chemistry. 
Only two of its compounds are considered in this place, the 
monoxid and the dioxid. 



CARBON MONOXID (Carbonic Oxid) 
Formula, CO. Molecular weight, 28. 

Preparation.— (1) Carbon monoxid (CO) is prepared by 
passing C0 2 over red-hot coals: C0 2 +C=2CO. (2) By inject- 
ing steam into red-hot coals, making water-gas: C + H 2 = 
CO + H 2 . (3) By burning carbon in an insufficient supply of 
air. (4) By heating oxalic acid with sulphuric acid, 



C 2 H 2 4 

Oxalic acid. 



CO + 

Carbon monoxid. 



co 2 

Carbon dioxid. 



+ 



H 2 0, 



the mixed gases being deprived of C0 2 by passing through sodium 
hydroxid. 




Fig. 35. — Carbon monoxid generated and washed in sodium hydroxid. 

Properties. — Carbon monoxid is a colorless, tasteless, inodor- 
ous gas with a specific gravity 0.967. It is almost insoluble in water 
and alcohol, but absorbed by ammoniacal solutions of cuprous 



CARBON MONOXID IOI 

chlorid, from which it may be reseparated by heat. It burns to 
C0 2 with a blue flame. This flame is seen burning on the surface 
of a hard-coal fire, which has at the grate an insufficient supply of 
air for complete combustion and hence burns first to CO and 
later at the surface to C0 2 . 

Toxicology. — Carbon monoxid often figures in cases of acci- 
dental poisoning, as it is the most poisonous constituent in the 
deadly gas used in cities for illuminating purposes (which may 
contain as much as 25 per cent.); in that escaping into houses 
from defective flues and open stoves; and in that given off by 
blast furnaces. The fatal effects are due to the power of CO to 
enter the blood by the lungs and to form with the coloring matter 
a fixed compound, thus destroying the function of carrying oxygen 
to the tissues. This function depends upon the reversible disso- 
ciation of oxyhemoglobin. 

HbO ±^ Hb + O. 

The compound with carbon monoxid, HbCO, is permanent and 
not dissociable. This property imparts an exceedingly poisonous 
character to an atmosphere containing more than 0.1 per cent.; 
when as much as 0.5 per cent, is present birds are killed in three 
minutes. The symptoms produced are dizziness, headache, 
nausea, weakness, convulsions, and coma. If a great part of the 
hemoglobin be saturated with it, death occurs promptly; if there 
be left unchanged enough to support life, the symptoms are still 
very grave and the recovery slow, debility and loss of appetite 
persisting for days. It is advisable to practise artificial respiration 
and inhalation of oxygen, with hypodermic injections of normal 
salt solution. 1 The altered blood must be renewed; stimulants, 
rest, and generous food are the main reliance. 

Detection after Death. — In a case of suspected poisoning 
a portion of the blood is studied by the spectroscope. If carbon 
monoxid be present, the blood will be of a persistently bright-red 
color, and the spectrum will show a double absorption band, 
resembling the double band of diluted oxyhemoglobin, but differing 
in that it is nearer the violet end (PL 4, Fig. 1, e). It differs 
further in not being reduced to the darker color of a single band, 
even when treated by an ammoniacal solution of ferrous tartrate. 
When treated on a white plate with sodium hydrate, specific gravity 
1.3, the poisoned blood forms a clotted mass, thin layers of which 
appear bright red, while normal blood turns to a dark slime which 
in thin layers is greenish brown. 

1 Normal or physiologic salt solution is usually made of the strength of 0.7 to 
0.9 per cent, of common salt, or 60 gr. to the pint of warm water, previously boiled, 
so as to sterilize it. One pint or quart is injected every hour, as required, beneath 
the skin of the buttocks or abdomen. 



102 



NON-METALS 



CARBON DIOXID (Carbonic Acid Gas, Carbonic Anhydrid) 

Formula, C0 2 . Molecular weight, 44. 

Occurrence. — Free carbon dioxid occurs in nature: (1) Dis- 
solved in the ground-water, and in large proportion a constit- 
uent of the ground-air, escaping from volcanoes, accumulating 
in caves, wells, mines, or any excavation. (2) As a product of 
putrefaction and of alcoholic fermentation it is abundant in the 
air of brewer's vats. (3) It is present in the expired air of animals; 
that exhaled from human lungs contains over 4 per cent, of C0 2 , 
while fresh air contains only 0.04 per cent. (4) In the combustion 
of wood, coal, or any organic substance the carbon is oxidized to 
form C0 2 . A burner of illuminating gas consumes nearly ten 
times as much air as a man, and produces six times as much carbon 
dioxid. 

Preparation. — Carbon dioxid can be obtained by the action 
of any non-volatile acid on any carbonate; but the most convenient 
source is white marble, a crystalline calcium carbonate, from which 
C0 2 is evolved by the action of hydrochloric acid. 



CaC0 3 + 

Calcium carbonate. 



HC1 = CaCl 2 + 

Calcium chlorid. 



H 2 + 



co 2 . 



The apparatus used is the same as that for the preparation of 
hydrogen (Fig. 28). As one volume of water dissolves an equal 




Fig. 36. — Pouring CO2 downward. 

volume of the gas it is wasteful to use the pneumatic trough. 
Being one half heavier than air, it is easily collected by downward 
displacement. 



1 



CARBON DIOXID IO3 

Properties. — Carbon dioxid is a colorless, suffocating gas with 
a slightly acid taste and smell, having a specific gravity of 1.529. 
Under a pressure of 50 atmospheres at 15.5 ° C. (6o° F.) it is con- 
densed to a transparent liquid. It will not burn, nor will it sup- 
port combustion, but heated to 1300 C. (2370 F.) it breaks up into 
CO and O. The chemical fire extinguisher is an apparatus for 
generating C0 2 under pressure, from which the gas is discharged 
in enormous volumes. Under the names of "black damp" and 
" choke-damp" it is an exhalation in mines, dreaded for its suffo- 
cative effects. Sometimes there flows from the seams of coal 
a natural gas known as "fire-damp," containing methane CH 4 , 
ethane C 2 H 6 , and hydrogen. In the pits of the mines it makes 
with air an explosive mixture. To prevent the accumulation of 
these gases ventilators are kept going constantly so as to displace 
them with air. If this is not done a lighted candle or match 
ignites the mixture with deadly violence, producing carbon dioxid 
or the "after-damp." 

Davy's safety-lamp has a chimney of wire gauze through which 
the flame cannot pass to ignite the explosive gases of the mine. 
The metal of the gauze cools the flame below the point of ignition. 

Aqua acidi carbonici, or soda water, is a solution of C0 2 in water 
under a pressure of 5 atmospheres. At ordinary pressure water 
dissolves an equal volume, and will take up this amount more 
for each addition of one atmospheric pressure. On opening the 
bottle the excess escapes as 4 volumes of gas (Carbonic Acid, 
p. 191). 

Detection. — Carbon dioxid extinguishes a flame and forms 
a white precipitate of carbonates when passed through the hy- 
droxids of calcium or barium. 

Ca(OH) 2 + C0 2 = CaC0 3 + H 2 0. 

Calcium hydroxid. Calcium carbonate. 

In a mixture of different gases, subjected to the absorbing 
powers of potassium hydroxid, a lessening of volume denotes 
C0 2 , and the amount of loss is a measure of the quantity of that 
gas. By aspirating a measured amount of any air through a weight 
absorption tube containing potassium hydroxid, the amount of 
C0 2 is shown by the increase of weight. 

The test fluid used by Fitz is dilute calcium hydroxid colored 
pink by phenolphthalein. Measured quantities of air are agi- 
tated with this fluid until it is decolorized. A table gives the C0 2 
in parts per 10,000 of the air used. 

Tests for Carbonates. — (1) Carbonates treated with hydro- 
chloric acid evolve C0 2 with effervescence; the C0 2 passed into 
lime-water produces a milky precipitate, CaCO s . 



104 NON-METALS 

(2) In neutral solutions of carbonates, barium chlorid causes 
a white precipitate of barium carbonate, which dissolves in acids 
with effervescence. 

Constant Proportion of C0 2 in the Atmosphere.— A full- 
grown man breathes every day about 10,000 liters of air, of which 
he absorbs about 500 liters of oxygen and exhales about 450 liters 
of carbon dioxid. Every breath contains enough C0 2 to make 
a milky precipitate when expired through lime-water. The 
average amount of C0 2 present in the open air of the country 
is 0.04 per cent., or 4 parts in 10,000. Notwithstanding the 
enormous quantities poured into the air from volcanoes, fermen- 
tations, respiration of animals, and combustion, the percentage of 
C0 2 is constant. There is a state of equilibrium in which the air 
continuously loses as much C0 2 as it receives. Some of the carbon 
dioxid is dissolved by the surface waters of the earth and fixed by 
the animal organisms — corals, shell-fish, etc., whose skeletons and 
shells make deposits of earthy carbonates. The greater part, 
however, is removed by plants which absorb C0 2 through their 
leaves and roots. In the leaf are cells like the leukocytes of the 
blood of animals. They contain green granules of chlorophyll 
which are energized by sunlight, but which are inactive in the dark. 
The leaf serves as a laboratory in which the chemical powers of 
the sunlight decompose the C0 2 , the plants retaining the carbon 
and exhaling oxygen in volumes equal to the absorbed gas. This 
restoration of oxygen compensates for the amount of that gas 
consumed in the various processes that produce C0 2 . 

Circulation of Carbon. — The life of organisms is sustained 
by the transformation of energy, most of which is the energy 
obtained by the oxidation of carbon. Plants lead a double life. 
They live and grow by oxidizing the food the sun forms by day 
in the leaf when they exhale oxygen. In the night when food- 
making ceases, but growth continues, they exhale, like an animal, 
a perceptible amount of C0 2 . Only by oxidizing the carbon com- 
pounds built up by plants, such as sugar, starch, oil, and gluten, 
can animals support their vital activities. The radiant energy 
expended by the sun is stored up by plants in amounts sufficient 
not only for self-maintenance, but also for the supply of energy to 
repair the waste occasioned by the life-process of all other organ- 
isms. The herbivorous animals consume carbonaceous food 
derived from plants, the carnivora in turn get their energy by 
feeding upon like material stored in the flesh of the plant eaters. 

In the oxidation product, C0 2 of the expired breath, animals 
return to the air the carbon which it had lost. The C0 2 is carried 
from the animal tissues to the lungs in combination mainly with 
sodium bicarbonate. In the lungs the bicarbonate breaks up, 



CARBON DIOXID IO5 

yielding the carbonates again and giving C0 2 and H 2 to the 
expired breath, thus reversing the reaction. 

2 NaHC0 3 ^ Na 2 C0 3 + C0 2 + H 2 0. 

Sodium bicarbonate. Sodium carbonate. 

Each of the two living kingdoms of nature supports the other in an 
eternal circuit of energy, obtained originally in kinetic form from 
the sun's rays and carried potentially by the carbon, on the one 
hand, and the oxygen, on the other. The elements C, H, N and 
O of the living plant or animal are like the parts of a mill-wheel 
which is moved by the stream of energy pouring from the sun 
to the earth; the circling wheel utilizes the energy to drive the mill 
of life. A part of the carbon of plants which does not soon return 
to the air is preserved in the storehouse of the soil as combustible 
substance. As peat deposited in bogs or in the fossilized form of 
coal, the carbon reappears in aftertimes to heat the boiler of the 
steam engine, and thus becomes the most abundant store of 
energy used in the mechanic arts. 

The average composition of air may be said to be the following: 

When inspired. When expired. 

Oxygen 20.60 vols. 16 vols. 

Nitrogen 76.90 " 77 " 

Argon 1. 00 " 1 " 

Carbon dioxid 0.04 " 4 " 

Aqueous vapor (about) 1.46 " 2 " 

Ammonia 

Ozone 

Nitric acid 

Marsh gas 

Sulphurous anhydrid | 

Sulphuretted hydrogen (in towns) J 

In the proportion of argon given above is included its con- 
geners, helium, neon, crypton, and xenon. 

Excess of C0 2 in Air. — When the circulation and diffusion of 
the air is interfered with by confinement in caves, wells, mines, 
vats, or badly ventilated rooms, it accumulates C0 2 , and when 
the proportion reaches 7 per cent, it is said to be contaminated. 
If the C0 2 be derived from respiration or combustion the air at 
the same time loses oxygen, so that an increase of C0 2 from these 
sources is most serious in its influence upon health. 

The cubic space for dormitories allowed each person should 
be, for the healthy, at least 400 cu. ft.; for the sick, occupying the 
same room day and night, 850 cu. ft.; for lying-in cases and those 
having offensive diseases, 1200 cu. ft. To calculate the largest 
number of persons that ought to sleep in a room, measure the 
length, breadth, and height of the room and multiply them to 
get the cubic contents. Divide the cubic contents by 400 and 
the quotient is the number of healthy occupants, which should 



- traces. 



106 NON-METALS 

not be exceeded if we would avoid contamination of the air from 
overcrowding. 

Poisonous Effects. — Pure carbon dioxid causes instant suffo- 
cation by spasm of the glottis. When the C0 2 is simply added to 
the air, as in the industry of making soda-water, or as in the dis- 
charge into free air from carbonated springs and other natural 
sources, an addition of 10 to 15 per cent, will render the air poison- 
ous, but not immediately fatal. A candle would still burn in this 
air, though dimly, but when the proportion reaches 16 per cent, 
the flame is extinguished. It would be fatal to go into any con- 
fined space where a candle will not burn. When the contamina- 
tion of confined air is due to respiration or combustion, and the 
reduction of oxygen corresponds to the increase of C0 2 , we feel 
oppressed by 0.1 per cent., and instinctively escape from it. 
Greater discomfort is produced by 1 per cent.; headache, dizziness, 
and nausea may be caused by 2 per cent. ; an atmosphere containing 
3 per cent, does not kill, though it causes profound disturbance of 
health, but 5 per cent, may be fatal from asphyxia. 

Treatment. — The indication is to get into the lungs a large 
amount of pure air or oxygen as quickly as possible. 1 To do 
this, the patient must be instantly removed to fresh air, and arti- 
ficial respiration practised with inhalations of oxygen. Respiration 
is stimulated by rhythmic pressure on the chest, traction of the 
tongue, slapping with a wet towel, galvanism, and friction of the 
extremities. These measures must be kept up for an hour, if 
necessary. When breathing is established, warm applications 
should be made to the extremities, and the body well wrapped 
in woolens, while coffee or brandy is administered internally. 

The Atmosphere. — The chemical constitution of the atmos- 
phere has been stated above. The 20.6 per cent, of oxygen sup- 
ports animal life; the 76.9 per cent, of nitrogen serves to dilute 
the oxygen; the 0.04 per cent, of C0 2 and the trace of ammonia 
nourish plants; water, to the extent of 1.46 per cent., favors the 
absorption of these foods and ozone purifies the air. 

Physical Properties. — A liter of air weighs 1.293 gm. Having 
covered an open receiver with the hand and removed the air with 
an air-pump, the pressure of the atmosphere is felt as a force of 
15 lbs. on every square inch (1033.3 gm. on every square cen- 
timeter). The whole body must support the pressure of several 
tons, and that it is able to do so is due to the fact that the pressure 

1 It often happens that the patient is first seen lying unconscious at the bottom of 
a well or pit or vat. Rescue seems impossible because others descending are 
instantly suffocated. In such cases great success has followed the following pro- 
cedure: A condenser of oxygen, holding 240 gallons of the gas compressed in a 
cylinder, is obtained from a hospital or a theater using oxygen for the oxycalcium 
light. Through a hose reaching to the bottom of the pit the gas is discharged not 
only to revivify the patient, but to displace the C0 2 , so that others can descend to 
his assistance. 



CARBON DIOXID 107 

is exerted equally in all directions, thus canceling the pressure 
on any one point. 

The variations of atmospheric pressure from day to day, or at 
different heights, are measured by the barometer. In its simplest 
form this instrument is a strong, straight glass tube, about 33 in. 
(800 mm.) in length, closed at the top. The lower end, which is 
open, dips into a small cistern of mercury. This tube is first filled 
with mercury and then inserted in the cistern with the open end 
under the liquid. The mercury of the tube falls to a point about 
30 in. (760 mm.) from the level of the cistern. The unoccupied 
space above the mercury is a vacuum. The pressure of the air 
outside upholds the column inside. As the air grows heavier 
the pressure forces the mercury higher; as the air declines in 
pressure, the mercury falls. In ascending a mountain the column 
of air above is reduced in height, and, therefore, the barometric 
column falls i in. for every 900 ft. of elevation. 

Gases are highly compressible, shrinking in volume regularly 
as the pressure increases (Boyle's law). On the other hand, the 
volume increases regularly with equal additions of absolute tem- 
perature (Charles' law). To compare the volumes of gases observed 
at different times, it is necessary that the pressure of the air and 
the temperatures at the times of observation be alike. As this is 
practically impossible from day to day, or hour to hour, it has been 
agreed to reduce the observed volumes of gases to standard condi- 
tions. By means of a formula the observation is converted to the 
standard barometric pressure of 760 mm., and at the standard tem- 
perature of o° C. 

y,_ V(b-W) 

760(1 + 0.00366 T) 

In this formula: V = volume required; V = the volume ob- 
served; b = barometer in mm.; w = tension of aqueous vapor 
(table, p. 40); T = observed temp. Centigrade (p. 30, footnote). 

Recent studies on the expansion of very dilute gases show that 
at a certain stage of dilution the ability to expand is much less- 
ened. This justifies the inference that the air does not extend 
indefinitely into space, becoming progressively more attenuated, 
but that at a distance of two hundred miles, more or less, it has 
a definite limit. 

When air is compressed 2000 pounds on the square inch, 
cooled with cold water, and then permitted to expand, it makes 
a low temperature for cooling another portion of compressed air. 
This in expanding cools another portion to a much lower tem- 
perature and, repeating this cycle of operations for the third time, 
the compressed air in expanding through a small opening is cooled 
below its critical point and liquefies. 



108 NON-METALS 

Liquid air can be obtained in any quantity by the expenditure 
of power. It is a bluish mobile liquid boiling at — iqo° C. 
( — 376° F.), and is used for procuring that temperature for experi- 
mental purposes. Immersed in it mercury freezes so hard that 
a piece can be used to hammer a nail; rubber and meat become 
as brittle as thin glass, alcohol solidifies like ice. Many forms 
of bacteria survive this exposure with only a temporary suspen- 
sion of vitality, and seeds of grain and peas after hours of immer- 
sion showed subsequent power of germination. As the air boils, 
the first more volatile portion extinguishes a flame; it is nitrogen. 
After a time the boiling vapor starts a glowing ember into flame, 
and we find that the liquid left is nearly pure oxygen, which has 
a higher boiling-point than the nitrogen. 





N. 


O. 


N 2 . . 


. . 28 


16 


N 2 2 . . 


. . 28 


32 


N 2 3 . . 


. . 28 


48 


N 2 4 . . 


. . 28 


64 


N 2 5 - • 


. . 28 


80 



CHEMICAL PHILOSOPHY 

In another place (p. 70) illustrations have been given of Dalton's 
first law, that of Definite Proportions: i. e., A definite compound 
always contains the same elements, united in the same proportions. 

There are five compounds of nitrogen and oxygen. The form- 
ulas, names, and compositions by weight are as follows: 

Nitrogen monoxid or Nitrous oxid. 
Nitrogen dioxid or Nitric oxid. 
Nitrogen trioxid or Nitrous anhydrid. 
Nitrogen tetroxid or Nitrogen peroxid. 
Nitrogen pentoxid or Nitric anhydrid. 

These compounds are illustrations of Dalton's second law, that 
of Multiple Proportions: When two bodies, simple or compound, 
unite in several proportions, the weight of one being constant, the 
weights oj the other vary according to a simple ratio. When com- 
posed of two elements they are said to be binary. In nomen- 
clature the name of the electropositive element in full is placed 
first; then follows the name of the electronegative element, with 
a suffix derived from the Greek numerals and the termination id. 
In an older method the name of the electropositive element was 
modified by adding -ic or -ous to the first syllable of the electro- 
positive element. Nitrous means less and nitric means more of 
the other or electronegative element. For the other compounds 
the prefix hypo- means less and per- means more of the electro- 
negative element. 

In the presence of water the first, third, and fifth of the above- 
named form acid ternary compounds of three elements, nitrogen 
with hydrogen and oxygen, as follows: 

H 2 N 2 2 or HNO Hyponitrous acid. 

H 2 N 2 4 or HN0 2 Nitrous acid. 

H 2 N 2 6 or HNO3 Nitric acid. 



ATOMIC THEORY IO9 

There is another generalized statement of facts, developing 
logically from the first and second laws — Equivalent Propor- 
tions: The proportions in which two or more bodies unite with 
another is either the same as that in which they unite with them- 
selves or a simple multiple of it. 

ATOMIC THEORY 

In studying the phenomena of allotropism of oxygen and 
carbon (see pp. 74 and 99) the conclusion becomes inevitable that 
nature, as we know it, behaves as if it were composed of minute 
separate particles, variously grouped in different bodies and in 
allotropic forms of the same substance. This conception came 
early in the history of thought, the first definite statement of the 
doctrine of atoms being attributed to Democritus (400 B.C.). As 
further developed by Lucretius, it may be summarized as follows: 
The bodies which we see and handle, which we can break in pieces 
and destroy, are composed of smaller bodies which we cannot 
see nor handle, which are always in motion, are centers of energy, 
and are not broken in pieces nor in any way destroyed. In 
the recent century of great chemical and physical discoveries 
each new fact has found a place in the structure of this theory. 
All attempts have failed to account for chemical phenomena on 
the opposed hypothesis of the homogeneous structure of matter. 
The only consistent view of matter is that it is not uniform and 
continuous throughout, but grained. The grains are molecules 
(see p. 28) which have still smaller constituents, atoms. The 
-atoms are undestroyed by the chemical force which keeps them 
combined in molecules and which controls their movements and 
associations. To these properties Dalton, in 1808, proposed that 
there be added others, to wit: (1) all the atoms of any one element 
have equal mass or weight; (2) the atoms of different elements 
have different weights; (3) the atomic weights be related as are 
the combining weights. 

As it is not divided in chemical reactions, the atom is the 
smallest quantity of an element that can enter into chemical 
combination. 1 When two elements combine, one atom of one 

1 Recent study of radio-active metals (p. 247) has established certain facts of 
wide range that do not fit into the atomic theory unless the intellectual conception 
of the atom be elaborated. The new conception symbolizes the new facts by giving 
a mechanical interior structure to the atom. It is conceived that in the sphere of the 
atom are a number of smaller corpuscles (electrons with a mass one-one thousandth 
that of the hydrogen atom), acting as a unit because in a state of equilibrium which 
resists the separating power of chemical operations and hence just so far justifies 
the assumption that atoms are indivisible. The atom-complexes of the radio-active 
elements, however, are in a state of unstable equilibrium, exhibiting energy in the 
form of heat, light, etc., while the atom-complex as a whole, losing some electrons, 
changes in properties as it declines in mass to stable forms which are permanent. 



1 10 NON-METALS 

element is placed in juxtaposition with one or more atoms of 
the other. It follows that the weights of two elements uniting 
will be in the same proportion as the constant weights of their 
atoms. This is the explanation of the law of definite or con- 
stant proportions. Thus, if the relative weights of atoms of 
sodium and chlorin are as 23 to 35, and combination is simply 
juxtaposition, then sodium chlorid can contain its elements only 
in the proportion of 23 parts of sodium to 35 of chlorin. 

Again, if one element, C, forms two compounds with another 
element, O, the first one of which contains one atom of C and 
one atom of O and the second contains one atom of C and two 
of O, it is plain that the masses of O which unite with the fixed 
mass of C must be in a ratio by a whole number. Thus, 12 
weights of C unite with 16 of O to make CO. But as C forms, 
another compound to the constant weight 12 of C, it can not have 
less than 16 of O, for that would be to split an atom, which is. 
postulated to be impossible. The mass of O must be either the 
first weight, 16, or some simple multiple, such as 1 : 2, so it takes 32 
of O and forms OCO or C0 2 . By almost universal consent 
chemists refer all the facts of their science to the one general law 
above stated — that is, that elements are composed of atoms having 
the same weights for the same kind, but different weights for 
different kinds. By means of this law the chemist determines, 
not only the nature and number of the atoms in a molecule, but 
also their arrangements. In no other way can we account for the 
compounds called isomeric, which show that two or more distinct 
substances may yet have the same number of the same atoms in 
the molecule. 

As stars in a system are kept in place by gravitation, so in a 
complex molecule atoms in various groups are held together by 
chemical attraction. A molecule of common alcohol, like that of 
methyl-ether, contains one atom of oxygen, two of carbon, and six 
of hydrogen. There is sound experimental basis for the conclu- 
sion that, although they have the same elements in the same pro- 

.CH3 
portion, the groups of atoms in methyl-ether are O/ and of 

X CH 3 
alcohol are HO.CH 2 . Powerful external forces may break up the 

I 

CH 3 

mutual attraction of large groups, but only to prove that the mem- 
bers of a smaller group have the greatest attraction for one another 
by the persistence of the original arrangement of their atoms. The 
atoms of the group CH 3 remain subject to each other's influence; 
through many vicissitudes and varying associations. 



ATOMIC THEORY III 

The atomic weight (A. W.) of an element is the weight of one 
atom of that element as compared with the weight of an atom 
of hydrogen. (For "subatomic matter," see p. 250.) 

The molecular weight (M. W.) of a substance is the weight of 
its molecule, as compared with the weight of an atom of hydrogen. 

As all gases are affected equally by temperature and pressure 
their molecular constitution must be alike. The law of Avogadro 
assumes that equal volumes oj all gases at the same temperature and 
pressure contain an equal number of molecules. It follows from 
this law that the molecular weights of gases are proportional to 
the weights of equal volumes — that is, to their specific gravities. 
The molecular weight is the sum of the atomic weights; hence 
if hydrogen be the unit, its molecular weight is 2, there being 2 
atoms in its molecule. To obtain the molecular weight of another 
gas, all that is necessary is to double its density. The vapor 
density is the specific gravity with hydrogen =1. M. W. = 2X 
V. D. (H=i). Expressed in terms of ordinary specific gravity 
(air=i), we must allow for the fact that air is 14.43 times heavier 
than hydrogen; then the molecular weight of a gas equals the 
specific gravity multiplied by 14.43 an d by 2; or M. W. = 28.86 X 
S. G. (air=i). Thus: the density of ozone (H = i) is approx- 
imately 24, which when doubled becomes 48. The weight of each 
atom being 16, which is one-third of 48, there must be three atoms 
in its molecules and its formula must be 3 . 

From what has been said above it might be expected that in 
chemical combinations of elementary gases the volumes entering 
into the union would hold some simple relation to each other. In 
fact this is Gay-Lussac's law. Moreover, the product of the reac- 
tion (the compound gas) has the volume of a simple multiple, usu- 
ally 2, even when the original single volumes were 3 or 4. For 
example: when united, 

1 vol. of hydrogen -j- 1 v °l- °f chlorin yield 2 vols, of HC1. 

2 vols. " -f- 1 " sulphur " 2 " H 2 S. 

2 " " -f- I " oxygen " 2 " steam. 

3 " '< -j- 1 «« nitrogen " 2 " NH 3 . 

Summary. — A molecule is the smallest particle of a substance 
that exists free and stable. 

An atom is the smallest characteristic part of an element that 
is combined in the molecule by chemical action. 

A compound is composed of molecules which contain two or 
more different kinds of atoms united. 

An element is composed of molecules which contain but one 
kind of atom. 

An electron is the negatively electrified particle contained in all 
atoms, and of which there are at least 1000 in a hydrogen atom. 



112 NON-METALS 

Chemical union is due to electric attractions; electronegative 
ions have a few more electrons than exactly balance their positive 
electricity; electropositive ions have a few less. When they 
meet they unite in a neutralized molecule (pp. 46 and 50). 

Symbols and Formulas. — In place of records of composi- 
tion and lengthy descriptions of reactions it has been found con- 
venient to use a shorthand system of symbols and equations. 
The symbol of an element is usually the initial letter of its name 
(English or Latin); when the names of two or more elements 
have the same initial, a second letter is added in smaller type. 
This second letter is the next vowel or a prominent consonant. 
Thus, Boron, Barium, Berryllium, Bismuth, and Bromin have the 
symbols B, Ba, Be, Bi, and Br, respectively. The choice of the 
single initial is given to the non-metal — in this case to Boron. 

The formula of a compound is made by printing as close as 
the types permit the symbols of the constituent elements: thus, 
copper oxid is CuO. 

The chemical symbol has a much more complex function than 
that of an algebraic one, like x and y, which stand for simple 
quantities. The chemical symbol represents, first, the name of an 
element; second, one atom; third, a constant definite proportion, 
called the atomic weight; fourth, a single gas volume. Thus, 
O stands for oxygen, 1 atom, 16 weights, and 1 volume. 

The formula of a compound denotes the name of its elements, 
the atoms in one molecule, the constant molecular weight, and 
two gas volumes. 

Thus, H 2 2 stands for hydrogen dioxid, 4 atoms in its mole- 
cule, a molecular weight of 34 (2 for the H 2 and 32 for the 2 ), 
and 2 gas volumes. It will be observed that when the molecule 
contains two or more atoms of the same kind the formula shows 
it by the small coefficient following, placed below the line. Thus, 
H 2 0, C0 2 . 

If it be desired to express more than one molecule of a com- 
pound, a large figure is used as a coefficient before the formula; 
thus, 2HNO3 represents not simply 2 atoms of hydrogen, but 2 
molecules of nitric acid. 

Three different kinds of formulas may be used to represent 
the same compound. When it is desired to express the com- 
position only, an empiric formula is used, which gives in the 
smallest number the proportions of the atoms. A molecular for- 
mula is a rational attempt to give the actual number of atoms in 
the molecule, and this may be a multiple of the empiric formula. 
When there is experimental ground for assuming that the inter- 
nal grouping of the atoms is known, the facts are indicated by 
the arrangement of the symbols of the atoms, thus making the 



PLATE i, 





No 

oo 

ooo„ 

o°o°o o?p o o0 

OP 



•%•/ 






BO 



3P 




Atomic Theory of a Hydrocarbon Flame. 

The red discs are oxygen atoms, the black are carbon, the blue are hydrogen ; 
the black circles in the yellow zone are incandescent carbon atoms emitting light. 
The products of the combustion are water and carbon dioxid. 



ATOMIC THEORY 1 13 

formula constitutional. Thus, ferric hydroxid may be denoted 
by either of the following formulas: 

Empiric and molecular FeH 3 3 . 

Constitutional Fe(OH) 3 . 

Nascent State. — When an element has just been released from 
combination, it is observed to have more powerful attractions than 
are shown by it after the first moment of new birth has passed. 
This transition phase of higher energy has received the name 
nascent state. It is often purposely produced to secure the highest 
capability of the element for effecting chemical changes. Ac- 
cording to the atomic theory, the transient state is one of single 
atoms energetically drawing others to them. With free affinities 
they are ready for fresh unions. Finding no dissimilar element 
to attract, they must at last combine with like companions to 
make stable molecules of the same elements. The atoms are 
now without free affinities, tied up in a combination which must 
be broken afresh before they can form another with atoms of a 
different element. 

It must be borne in mind that the atom is only a figment of 
the scientific imagination, although this mechanical conception is 
in the highest degree useful for a working chemist as well as for 
the philosopher. No other theory has harmonized so many chem- 
ical facts, or has proved more fruitful in discoveries than this. 

A graphic picture is here shown (Plate 1) of what the chemist 
imagines to occur when he explains the burning of common illu- 
minating gas in a luminous flame: 

CH 4 + 2 2 = C0 2 + 2H 2 0. 

It must be remembered that in this plate nothing is postulated 
of the atom as to its color or form or relations in space. 

Carbon atoms are represented by black discs, which become 
bright at a high heat; hydrogen atoms are blue; oxygen, red. 
These colors serve simply to distinguish the elements. 

Molecules of CH 4 stream out at the burner, a match heats it 
to the point required to unite it with oxygen. The free oxygen 
of the air in molecules, when heated, dissociates into atoms, 
which at once unite with the hydrogen of CH 4 to form molecules 
of H 2 0. Their union causes heat sufficient to raise the carbon 
atoms of CH 4 to incandescence, furnishing light as they pass 
through the hot zone. At the outer margin they meet oxygen 
atoms heated and combine with them to form C0 2 . At the center 
is the combustible gas CH 4 yet unburned, surrounded by a cone 
of incandescent carbon which deposits soot on a cold surface 



114 NON-METALS 

and on the outer edge is the hottest zone due to the final burning 
of the carbon. If sufficient air be mixed with the gas before 
ignition, as in a Bunsen burner, or if air be blown in by a blow- 
pipe, a more intense heat is obtained all through the flame. The 
illuminating and soot-making powers then disappear, because the 
carbon is burned once with the hydrogen and there is no luminous 
cone of white-hot carbon atoms. 

Valence, Atomicity, Quantivalence.— When two substances 
have acted upon each other and caused transformations, they are 
said to have entered into reaction} 

The atomic weights of the elements do not express their rel- 
ative values in the mutual reactions. 

In the equation Zn + H 2 S0 4 = ZnS0 4 + H 2 , i atom of zinc 
proves its equal value to 2 of hydrogen by exchanging for the 
hydrogen atoms, taking their place. The zinc is accepted by the 
S0 4 as being equal in chemical power to the 2 hydrogen atoms. 
In the same way 1 atom of chlorin is substituted for 1 atom of 
hydrogen; 1 of oxygen for 2 of hydrogen; 1 of nitrogen for 3 
of hydrogen; 1 of carbon for 4 of hydrogen; 1 of phosphorus 
for 5 of hydrogen; and 1 atom of sulphur for as many as 6 atoms 
of hydrogen. This value of a combining atom compared with 
that of an atom of hydrogen is called its valence, valency, or quan- 
tivalence. If its valence is equal to one of hydrogen, it is monovalent 
or univalent and is termed a monad, such as CI, Br, I, K, Na, Ag; 
one of double value is divalent or bivalent and is termed a dyad, 
as O, S, Cu, Hg, Zn, Ca; one of triple value is trivalent and called 
a triad, as P, As, Sb, Bi; one of quadruple value is tetravalent 
or quadrivalent, and is called a tetrad, as C, Si, Al, Pt, Pb; one of 
quintuple value is pentavalent or quinquivalent, called a pentad, 
as P.; one of sextuple value is hexavalent or sexivalent, and called 
a hexad, as S. 

The cause of valence has not been determined, though a recent 
speculation concerning it may prove of some help. The work 
of Faraday embodied in his laws (p. 52) showed that the electric 
charge of an ion was proportional to its valence. As nearly all 
chemical action is between charged ions, one charge may stand 
for univalence, then a bivalent ion is one that carries two charges, 
the trivalent, three, and so on. The amounts of the different ions 
carrying the same charge are in the proportion of the atomic 
weights of the ions. To set free a bivalent ion requires twice as 
much electricity as to free a univalent one and the trivalent thrice 

1 The word reaction is also used to describe the effect of acids and bases on cer- 
tain colored indicators, such as litmus. The reaction is neutral when it does not 
alter the color of either red or blue litmus; it is acid when it turns blue litmus red; 
alkaline when it turns red litmus blue. 



ATOMIC THEORY 115 

and so on. No ion has more than eight charges (octivalent), and 
none has less than one, which is that of hydrogen. Each valence 
is sometimes referred to as a bond or link of attachment. It is 
sometimes symbolized by radiating strokes and sometimes by 
accent marks and Roman numerals, placed above and to the 
right of the symbol of the element, thus: 

H- H' 

- O - O" 

V 

N N'" 



- C - . C IV 

I 
W/ 

P Pv 

A 
V 
- S - S VI 

A 

Variation of Valence. — The valence of an element is not a 
fixed and unchanging quantity; thus, nitrogen in nitrous oxid, N 2 0, 
is a monad; in ammonia, NH 3 , it is a triad, and in ammonium 
chlorid, NH 4 C1, it is a pentad. 

In view of the fact that the valence of an element may vary 
with the temperature, with the nature of the other substance, and 
with unknown conditions, it cannot be considered an absolute 
endowment of the atom, but only as a. statement of its attractive 
power in the special class of compounds being studied. 

Graphic Formulas. — In another place (p. no) two methods of 
notation were used for one substance. These were called the 
empiric and constitutional formulas of ferric hydroxid. In addi- 
tion to these methods of noting the results of discovery chemists 
sometimes fix the impression they have received as to the internal 
arrangement of a complex molecule by a graphic formula. When 
it is desired to show that the iron in ferric hydroxid acts as a triva- 
lent atom, and that the hydroxyl groups are monovalent, the following 
graphic form is used: 

H 

I 

O 
I 
Ferric hydroxid . . Fe(OH) 3 . . H-O-Fe-O-H. 



1 16 NON-METALS 

Classification of the Elements. — In an earlier section (p. 65) 
the elements to be studied were grouped in classes for emphasizing 
certain important properties. That arrangement, while serving the 
purpose at that point, does not pretend to be the only one of value. 
For different needs there are different lists, more or less special or 
one-sided. The ordinary table is alphabetic, the only claim made 
for it being that it is easy for reference. 

In the periodic system Mendelejeff has grouped them by their 
valence, and the elements thus allied he has placed in the order 
of their atomic weights, so as to emphasize the significant fact 
that they differ from each other by approximately a multiple of 
the number 8. It has been shown that with this regular numeric 
increase in atomic weights there is a corresponding progression 
of properties, thereby raising the presumption that the physical 
and chemical properties of elements, and also the constitution and 
properties oj their compounds are periodic junctions of the atomic 
weights (Mendelejeff' s periodic law). 

When the atomic weights were first calculated hydrogen was 
taken as 1, and oxygen was found to be 16. As nearly all the 
elements unite with oxygen, their atomic weights were calculated 
on the basis of = 16, and these weights have been in use many 
years. It has been discovered, however, that there was a mistake, 
and that if = i6, then H is not 1, but 1.008. The whole ques- 
tion is simply one of convenience, and as the table based on = 16 
is adjudged best by some of the most authoritative chemical 
societies, it is the one used in the present work. For the purpose of 
simplifying study in the body of this work, the nearest integer is 
used, the fractions being ignored. 

The table that follows on pp. 117 and 118 is not Mendele Jeff's, 
though it is based upon the periodic system. In perpendicular 
columns similar elements are grouped in sections by their numeric 
values. 

In the section where the valence is marked o will be found the 
argon family of atmospheric elements, which are unable to unite 
with other elements. In the next section, marked I., are hydrogen 
and the alkali metals. In the next, marked II., are the divalent 
alkaline earth metals and the heavy metals of the zinc family. The 
section marked III. contains trivalent boron, the earth metals, and 
the corresponding heavy metals, gallium and indium. Section IV. 
contains two tetravalent non-metals and metals of the titanium 
family, along with those of the tin family. Section V. contains 
elements that are pentavalent or trivalent, such as the nitrogen 
family. In Section VI. are elements that are divalent or hex- 
avalent. In Section VII. are the halogens, which are univalent 
or heptavalent, and three metals that are divalent on the one hand 



ATOMIC THEORY 



II 7 



or heptavalent on the other. In the last section are the metals 
which cannot be placed in any previous class — the iron and the 
platinum families. 

Elements Arranged in Arithmetic Progression according to Atomic 
Weight and Valence 



Name. 



Helium 

Neon 

Argon 

Krypton 

Xenon 



Hydrogen .... 

Lithium 

Sodium {natrium) 
Potassium {kali- \ 

um) j 

Rubidium .... 



Derivation. 



Gr. helios, sun . . 

Gr., new 

Gr., without energy 
Gr., hidden .... 
Gr., stranger . . . 



Gr., water-forming 
Gr. lithos, stone . . 
Eng. soda 

Eng. potash . . . . 



L. rubidus, red (its spectrum) 



Cesium | L. aaesius, sky-blue 



Gr. glykys, sweet 



Glucinum ) 

{beryllium) . J 
Magnesium ... I Magnesia, district in Thessaly . 

Calcium | L. calx, lime 

Zinc Ger. zink 

Strontium .... Strontian, a town in Scotland . 
Cadmium . . . . j Gr. cadmeia, calamine . . . . 

Barium \ Gr. barys, heavy 

Mercury : Name of planet 

Radium 



Boron . . . . , 
Aluminum . . 
Scandium . . 
Gallium . . . 
Yttrium ... 
Indium . . . 
Lanthanum . 
Neodymium . , 
Praseodymium 
Samarium . . 
Gadolinium . 
Terbium . . . 
Erbium . . . 
Thulium . . 
Ytterbium . . 
Thallium . . 



' Borax 

' L. alumen, alum 

Scandinavia 

L. Gallia, France 

Ytterby, a town in Sweden . . . 

From its indigo spectrum . . . 

Gr. lant)iano, conceal 

Gr. neo, new, and didymcs, twin 

Gr. praeseo, green, and didytnos 

Samarski, a Russian savant . . 

Gadolin, a. Russian chemist . . 

Ytterby, a town in Sweden . . . 

Ytterby, a town in Sweden . . . 

Thule, Northland 

Ytterby, a town in Sweden . . . 

Gr. tltallos, budding twig . 



Carbon 

Silicon 

Titanium . . . . 
Germanium . . . 
Zirconium .... 
Tin {stannum) 
Cerium .... 
Lead {plumbum) 
Thorium . . . . 



L. carbo, charcoal 

L. silex, flint 

L. Titanes, sons of the earth . 
L. Germania, Germany . . . 
Ar. zarkun, gold-colored . . 

Anglo-Saxon 

Planet Ceres 

Anglo-Saxon 

God Thor 



He 

Ne 

A 

Kr 

X 



H 
Li 

Na 

K 

Rb 
Cs 



Gl 

Mg 

Ca 

Zn 

Sr 

Cd 

Ba 

Hg 

Rd 



B 

Al 
Sc 
Ga 
Yt 
In 
La 
Nd 
Pr 
Sm 
Gd 
Tb 
Er 
Tu 
Yb 
Tl 



C 

Si 

Ti 

Ge 

Zr 

Sn 

Ce 

Pb 

Th 



o V 
= i6 



4.00 
20.00 

39-9° 

81.80 

128.00 



7-°3 
23.05 



85-5o 
132.90 



9.10 

24.30 
40.00 
65.30 
87.60 
112.20 
i37-4o 
200.00 
225.00 



11.00 
27.00 

44.00 
69.00 
89.10 
113-70 
138.80 
140.50 
143-50 
150.00 
156.10 
160.00 
166.30 
170.70 
173.00 
204.18 



12.00 

28.40 

48.00 

72.30 

90.60 

119.00 

140.20 

206.95 

232.60 



o"S 

H = l 



4.000 
19.900 
39.600 

81.200 

[27.000 



I.OOO 
6.97O 
22.880 



84.750 
I3I.9OO 



9.OOO 

24.IOO 
39.80O 
64.900 
86.950 
III. 550 
I36.4OO 
I98.50O 
223.OOO 



IO.90O 
26.9OO 
43.80O 
69.500 
88.300 
II3. IOO 
I37.600 
I42.500 
I39.4OO 
I49.2OO 
I55.800 
158.800 
164.700 
169.400 
I7I.9OO 
202.610 



II.9OO 
28.200 
47.800 
7I.9OO 
89.700 

118. 100 
138.000 
205.360 
230.800 



Valence. 



II. 

II. 
II. 
II. 
II. 
II. 
II. 
I. or II. 
II. 



III. 

III. 

III. 

III. 

III. 

III. 

III. 
III. or IV. 
III. or IV. 

III. 

III. 

III. 

III. 

III. 

III. 
I. or III. 



IV. 

II., III. or IV. 

IV. 

II. or IV. 

IV. 

II. or IV. 

III. or IV. 
II. or IV. 

III. or IV. 



Nitrogen .... Gr., niter-forming .... 

Phosphorus . . . Gr., light-bearing .... 

Vanadium .... Goddess Vanadis (Freya) 

Arsenic L. arsenicum 

Columbium 1 ^ , , . 

{niobium) . . \ Columbza 

Antimony {sti-1 T 

bium) . \ . } L - intitnomum 

Tantalum .... Tantalus (Gr. myth.) . . 

Bismuth Ger. (unknown origin). . 



N 
P 
V 
As 

Cb 

Sb 

Ta 
Bi 



1403 
31.00 
51-40 

75.00 

94.00 



182.60 
208.90 



13.930 
30-750 
51.000 
74.450 

93.000 

119.500 

181.500 
206.500 



III. orV. 

III. orV. 

II., III. or IV. 

III. orV. 

III. orV. 

III. or V. 

V. 
III. orV. 



n8 



NON-METALS 



Elements Arranged in Arithmetic Progression according to Atomic 
Weight and Valence — Continued 



Name. 



Derivation. 



£ bo 
0=i6 



6 bo 
H = 



Valence. 



Oxygen .... 
Sulfur (Sulphur) 
Chromium . 
Selenium . 
Molybdenum 
Tellurium . 
Tungsten (wol- 

framiunt) 
Uranium . 



Gr., acid-forming 

L. sulphur 

Gr. chroma, color 

Gr. selene, moon 

Gr. molybdos, lead 

L. iellus, earth 

Swed., heavy stone 

Planet Uranus 

~L.fluor, <~fluo, flow . . . . 

Gr. chloros, green 

L. magnes, magnet 

Gr. bromos, stench 

Rus. Ruthenia 

Gr. iodes, violet 

Gr. osme, odor 

Anglo-Saxon, iren 

Ger. kupfernickel 

Ger. kobold, goblin 

L. Cyprus 

Gr. rhodon, rose 

Planet Pallas 

Anglo-Saxon seolfor 

L. iris, a rainbow 

f Span, platina, dim. of plata 

\ silver 

Anglo-Saxon 



O 

s 

Cr 

Se 
Mo 
Te 

W 

U 



16.00 
32.06 
52.10 
79.00 
96.00 
127.00 

184.00 

238.60 



15.880 
31.830 
51-700 
78.600 
95-3°o 
126.500 

182.600 
237.800 



II., 

III. 



II. or VI. 
II. or VI. 
II. or III. 
II. or VI. 
III., IV. or V. 
II. or VI. 

IV., V. or VI. 

IV., V., VIII. 



Fluorin . . 
Chlorin . . 
Manganese 
Bromin . . 
Ruthenium 
Iodin . . . 
Osmium . . 



F 

CI 

Mn 

Br 

Ru 

I 

Os 



19.00 
35-45 
55-oo 
79-95 
101.60 
126.85 
190.80 



18.900 
35.180 
54.600 
79-34o 
100.900 
125.890 
180.600 



I. or VII. 

I. or VII. 
II., III. or IV. 

I. or VII. 
II., III. or IV. 

I. or VII. 

II. or IV. 



Iron {ferrum) 
Nickel. . . . 
Cobalt. . . . 
Copper . . . 
Rhodium . . 
Palladium . . 
Silver {argentum) 
Iridium . . . 

Platinum . . 

Gold (aurum) 



Fe 
Ni 
Co 
Cu 
Rh 
Pd 

t? 

Pt 
Au 



56.00 
58.00 
59.00 
63.60 
103.00 
106.60 
107.90 
193.10 

195-00 

197.30 



55.860 
58.250 
58.550 
63.100 
102.200 
106.200 
107.110 
191.700 

193.400 

195-700 



II. or III. 

II. or III. 

II. or III. 

I. or II. 

III. 

II. or IV. 

I. 

II., III. or IV. 

II. or IV. 

I. or III. 



CHLORIN (Chlomm) 

Symbol, Cl. Atomic weight, 35.45. 

This element occurs in nature chiefly in common salt (sodium 
chlorid), of which it constitutes more than one-half by weight. 

Preparation. — Chlorin is prepared on a large scale by elec- 
trolysis of a solution of potassium or sodium chlorid. Chlorin 
separates at the anode and hydrogen at the cathode; the sodium 
as hydroxid remains in solution. 

NaCl + H 2 = NaHO + H + CI. 

Sodium chlorid. Sodium hydroxid. 

For experimental purposes chlorin is prepared from sodium 
chlorid by first displacing the sodium with hydrogen to make 
hydrogen chlorid (hydrochloric acid), and then, by means of the 
oxygen of manganese dioxid, abstracting the hydrogen to form 
water. The first step is taken by the action of sulphuric acid: 

(1) 2 NaCl + H 2 S0 4 = Na 2 S0 4 + 2HCI 

Sodium chlorid. Acid sulphuric. Sodium sulphate. Hydrogen chlorid. 



CHLORIN 



II 9 



In the second stage the HC1 is broken up by the rich supply 
of oxygen in the manganese salt: 



2H 2 



CI, 



(2) 4HCI + Mn0 2 = MnCl 2 

Manganese dioxid. Manganese chlorid. 

The best method is to perform both stages at once by heating 
in a flask over a sand-bath a mixture of sodium chlorid and gran- 
ular manganese dioxid, 5 parts of each, with 12 parts of sulphuric 
acid and 6 parts of water previously mixed and cooled. The gas 
is collected in glass-stoppered bottles by downward displacement. 
In this reaction all the chlorin present is evolved, since the man- 
ganese is taken up by the sulphuric acid. From bleaching powder 
(calx chlorinata) a copious supply is obtainable without heat by 
the action of hydrochloric acid. 

Ca(C10)Cl + 2HCI = CaCl 2 + H 2 + Cl 2 . 

Calx chlorinata. Calcium chlorid. 

Any flask or wide-mouthed bottle will serve the purpose as a 
generator. It should be closed with a double-perforated stopper. 
Through one hole passes a dropping-funnel with stop-cock; 




p IG . 37 —Chlorin evolved from calx chlorata washed in water and dried in sulphuric acid. 



out of the other passes the delivery tube, which may enter a 
wash-bottle of water to get free from the hydrochloric acid fumes 
and another of sulphuric acid for drying; or, if absolute purity is 
not required, the gas may pass directly into the collecting jar. 
Being nearly two and a half times heavier than air, its density 
enables us to collect it in dry bottles by downward displacement. 



120 NON-METALS 

When the bottle-contents are greenish yellow throughout, it should 
be closed with a ground-glass stopper smeared with vaselin. Its 
solubility in water precludes the use of the pneumatic trough unless 
the water be warmed. Even the mercury trough is forbidden, 
because it combines with the mercury. 

Physical Properties. — Chlorin is a gas of a greenish-yellow 
color, having an unpleasant, irritating odor even when diluted with 
air. On inhaling, a sense of suffocation is felt in the chest and an 
irritation in the nose and throat, due to the corrosive action of the 
gas on the lining of the air-passages. Its specific gravity is 2.5. 
By cold [ — 34° C. ( — 29.2° F.)] and pressure it is converted into 
a greenish-yellow, oily liquid; and at still lower temperatures, 
— 102 ° C. (—152° F.), it solidifies in greenish-yellow crystals. 

Liquor Chlori Compositus, U. S. P.— Aqua Chlori.— This 
is a solution of 0.4 per cent, of chlorin with potassium chlorid 
and chlorin oxid. It is freshly made when wanted in a 2-liter 
flask, by warming for three minutes potassium chlorate, 5 gm., 
in hydrochloric acid, 18 c.c, diluted with an equal amount of 
water and adding water to dissolve the greenish gas evolved. 

2KCIO3 + 4HCI = Cl 2 + C1 2 4 + 2KCI + 2 H 2 0. 

Potassium Hydrochloric Chloric 

chlorate. acid. oxid. 

One liter of water under ordinary circumstances will absorb 
nearly three liters of chlorin, becoming the reagent chlorin-water. 
This solution has the color, smell, taste, and chemical and thera- 
peutic properties of the gas itself, but in a more manageable form. 
It should be protected from light by keeping in dark amber-colored 
bottles, otherwise a decomposition will occur. 

In direct sunlight chlorin quickly abstracts hydrogen from the 
water to form hydrochloric acid, oxygen being set free. 

H 2 + 2CI = 2HCI + O. 

This belongs to the class of photochemical effects, such as 
are seen in the processes of photography and the assimilation of 
carbon dioxid by green plants in the sunlight. The chemical 
powers reside chiefly in the blue and violet rays, which are shut 
out by reddish glass. 

Chemical Properties.— Chlorin has an atomic weight 35.45. 
Like oxygen it does not burn, but at ordinary temperatures dis- 
plays greater activity in supporting combustion than does oxygen. 
The velocity of its reactions produces sufficient heat for combustion, 
even when it unites spontaneously with other substances. Im- 
mersed in it, phosphorus takes fire without previous heating, 
powdered antimony forms a rain of sparks, and a warmed ball 



HYDROGEN CHLORID 121 

of dutch-metal foil becomes incandescent. 1 Moist chlorin com- 
bines directly at room-temperature with all metals except iridium, 
and with most of the non-metals. In all the cases of union above 
mentioned the compound is a chlorid of the other element. 

Toxicology.— Symptoms. — When inhaled in small amounts 
chlorin causes a suffocative feeling and cough. If taken undi- 
luted it causes difficult breathing, a painful sense of tightness in 
the chest, and violent cough with hemorrhage. Indirectly the 
nerve-centers are involved, producing stupor and even heart failure. 

Fatal Dose. — Fatal consequences are not apt to occur unless 
the subject is in delicate health, and the gas is taken with little 
admixture of air. 

Treatment. — Fresh air must be given at once, and the pain 
relieved by the inhalation of ether. The symptoms of acute 
bronchitis, narcotism, and enfeebled heart action must be treated 
by appropriate remedies. 

Detection. — The gas can be recognized by its odor and its 
bleaching action on moist litmus-paper. As chlorin-water it has 
the same properties, and in addition dissolves gold-foil. 

Direct Union of Chlorin and Hydrogen. — The intense attrac- 
tion that exists between hydrogen and chlorin is shown in many 
ways. If the two gases be mixed in equal proportions and the vessel 
placed in direct sunlight, a violent explosion occurs; if the mixture 
be kept out of strong light, the union likewise takes place, but quietly 
and slowly. After the union the green color is absent, and if the 
vessel be opened under water that liquid rises quickly in the bottle 
and acquires the sour taste and acid reaction of hydrochloric acid. 

An ignited jet of hydrogen continues to burn when introduced 
into a vessel containing chlorin, the flame changing from blue to 
whitish green. If the vessel be afterward rinsed out with water 
the water will taste sour and redden blue litmus, showing the 
formation of hydrochloric acid. 

Indirect Union of Chlorin and Hydrogen. — There are many 
compounds of hydrogen with carbon that lose their hydrogen in the 
presence of chlorin. A paraffin taper ignited will continue to burn 
at the mouth of a jar containing chlorin, but the carbon separates 
in dense clouds of soot. 

CH 4 + Cl 4 = 4 HC1 + C. 

Hydrocarbon. 

Uses in the Arts. — Although absolutely dry chlorin does not 

bleach, the moist vapor as a bleaching agent takes high rank. 

The native vegetable fibers are not white, and to make them 

acceptable to the eye linen, cotton, and paper must be bleached. 

1 In its wider sense combustion is any chemical process evolving a temperature 
of incandescence or 500 C. (932 F.). 



122 NON-METALS 

A convenient source of chlorin is the bleaching powder of com- 
merce, to be described later. Most color principles contain hydro- 
gen, which is partly directly removed by the. chlorin, but in the 
presence of water the action is much more decided. By decom- 
posing the water chlorin sets free active nascent oxygen, thus 
becoming an oxidizing agent. This oxygen instantly converts 
sulphurous acid into sulphuric acid, a higher oxygen compound: 



H 2 S0 3 + 


ci 2 


+ 


H 2 


= H 2 S0 4 


+ 2HC1 


Acid sulphurous. 








Acid sulphuric. 


Acid hydrochloric. 



Chlorin discharges the color of common anilin inks, but does 
not affect the carbon of printer's ink or india ink. This can be 
shown by blotting a printed page with common ink and dipping 
it into chlorin water, when the printed letters reappear as the 
writing ink fades away. 

As a deodorizer, chlorin breaks up the foul-smelling gases of 
putrefaction, hydrogen sulphid (H 2 S) and ammonia (NH 3 ), by 
abstracting the hydrogen and oxidizing the sulphur and nitrogen. 

As a disinfectant, chlorin poisons the bacteria that produce the 
infectious diseases. To do this it must be in solution, as the gas 
is not effectual in killing them or in materially lessening their 
activity. Some of the best bactericides are compounds of chlorin 
or its associate, iodin. 

Hydrogen Chlorid (HC1) (Hydrochloric Acid Gas).— It has 
been stated above that this compound can be formed by the 
direct union of its elements, but for laboratory purposes it is 
more conveniently prepared by the action of sulphuric acid on 
common salt (p. 135); gentle heat is required to disengage the gas 
HC1, leaving sodium sulphate in solution. 

The gas can be prepared without heat by removing water from 
commercial hydrochloric acid. Using an apparatus like the 
generating flask, Fig. 37, nothing but concentrated sulphuric acid 
is placed in the flask. Gradually the hydrochloric acid is dropped 
in through the tap-funnel. A colorless gas is evolved which is 
a little heavier than the air (specific gravity 1.247), an d by cold 
and pressure becomes first a liquid, and at — 113 C. (—173° F.) 
becomes a solid. Having collected some of the gas in an inverted 
test-tube over a mercury trough, a few cubic centimeters of water 
may be blown through a bent pipet so as to rise through the mer- 
cury and make a top layer about 1 inch deep. The mercury now 
ascends, thus showing that the gas has been absorbed by the water. 
If the water were colored blue by litmus, it is turned red, and 
a piece of magnesium allowed to float up to the surface of the mer- 
cury, causes effervescence of hydrogen and fall of the mercury, 
thus showing that hydrochloric acid has been formed. The 



ACIDS, BASES, AND SALTS 1 23 

volume of hydrogen evolved equals half that of the original hydro- 
gen chlorid. By raising the tube out of the mercury, air enters to 
form an explosive mixture with the hydrogen. 

ACIDS, BASES, AND SALTS 

Solubility of Hydrogen Chlorid.— One of the most remark- 
able properties of hydrogen chlorid is its solubility in water. 
At ordinary temperatures 450 volumes will dissolve in 1 volume 
of water, evolving a large amount of heat. The heat is an indica- 
tion of a special process different from simple solution. The 
volumes of most gases absorbed by water are not nearly so great 
as 450. Henry's law for the absorptive property of water for 
gases is that the amount absorbed is proportional to the pressure 
(p. 91). In the case of the absorption of hydrogen chlorid the 
effect of pressure is discernible only to a slight degree. These 
facts make it appear that the atoms of hydrogen chlorid in solution 
are no longer coupled as in their former condition of a dry molecule. 
Other evidence of a conversion is seen in the fact that pure anhy- 
drous hydrogen chlorid compressed to a liquid has no acid proper- 
ties. To develop these some new relation of its atoms is needed, 
and this change is brought about by the solution in water. This 
molecular change is explained in the following way: When the 
gas dissolves only a part remains as unchanged molecules, and 
hence subject to Henry's law. Another part is thrown into a 
different condition and, therefore, acquires new properties (p. 131). 

Further confirmation of this view is shown in the fact that the 
highly volatile hydrogen chlorid in dilute solution does not lower 
the boiling-point of water, but raises it. This, too, is an exception 
to the rule for aqueous solutions of volatile substances, which 
usually have an opposite effect. These peculiarities in hydrogen 
chlorid are best explained by the theory of an abnormality in the 
condition and number of the ultimate particles when they are 
dissolved in water. Solution has apparently increased the num- 
ber of particles, which could only be done by some sort of dis- 
sociation of the constituent hydrogen and chlorin in the molecules 
of hydrogen chlorid. 

Acids. — In calling the aqueous solution of hydrogen chlorid 
an acid we attribute to it certain properties common to a large 
class. The word is derived from acies, sharp, and originally 
described the taste only. It was discovered afterward that all 
substances which have this taste possess a common effect upon 
the blue dye, litmus, turning it red (PL 5, Fig. 1); and further, 
that in the presence of metallic zinc or magnesium they yield 
hydrogen. Powdered magnesium will cause effervescence of 
the inflammable gas, not only from hydrochloric acid, but also 



124 NON-METALS 

from any acid liquid, even the juice of subacid fruits. While 
hydrogen may be regarded as the element giving the acid its powers, 
we must not lose sight of the fact that it does not always carry this 
acid endowment with it. If it did, then water and the neutral 
compounds, alcohol, the paraffins, and fats, would be acid. 

The hydrogen constituent is shown in formulas of the follow- 
ing strong acids: hydrochloric, HC1; sulphuric, H 2 S0 4 ; nitric,, 
HN0 3 ; phosphoric, H 3 P0 4 . 

Bases. — An acid that tastes sour, reddens litmus, and takes 
a metal in place of hydrogen, loses all these properties by the 
addition of sodium hydroxid (caustic soda). The change in the 
color of acid-red litmus to blue is so sharply defined that it is. 
customary to depend on that alone as an indicator of the simul- 
taneous loss of all acid properties. If the acid be hydrochloric 
and litmus-paper have been used, on evaporation there is left in 
the dish a white crystalline compound which tastes neither sour 
nor alkaline, but salty. It is easily identified as kitchen salt, 
sodium chlorid, and is produced according to this reaction: 
HC1 + NaHO = NaCl + H 2 0. 

Sodium hydroxid. Common salt. 

Neutralization. — The process just described of neutralizing 
the acid properties and forming water and a salt can be performed 
by any one of a large class of substances known as bases. They 
are compounds of metals with hydroxyl (HO), and are said to be 
basic because they constitute the solid residue when the more 
volatile acid constituent of the salt is driven off by heat. The 
soluble bases, of which the caustic alkalies, soda, potash, and 
ammonia, are the most marked representatives, are characterized 
by their opposition to the acids in restoring blue litmus, and in 
overcoming their acid taste and hydrogen-generating property. 
This accomplished, we have products that are neutral, such as 
water and common salt. In brief: acids and bases have the power 
oj destroying the properties of each other. 

Definite Weights Engaged. — In forming a salt, water is also a 
necessary product, because the hydroxyl (HO) of the base attracts 
the hydrogen just liberated from the acid. The numeric expres- 
sion of this affinity is that the molecular weight, 17 gm., of hy- 
droxyl in the base is required to hold the atomic weight, 1 gm., of 
hydrogen. Until this element is thus held the acid properties persist. 

Acidimetry. — By using a solution of sodium hydroxid or 
potassium hydroxid of known strength we have a standard of 
hydrogen-fixing power, and units of it will be equivalent to definite 
amounts of acid in the solution neutralized. To make the two 
solutions of reciprocal strength and their neutralizing power 
equivalent to 1 gm. of hydrogen, they should be accurately tested 



ACIDS, BASES, AND SALTS 1 25 

in advance. The standard adopted is the normal solution, one 
for which the acid is weighed in a sufficient number of grams to 
contain 1 gm. of acid hydrogen, and then dissolved in sufficient 
volume of water to make 1 liter of the finished product. Such 
a solution is sometimes called a gram-atom, to imply that there is 
in it the atomic weight of hydrogen, 1, in grams. Oxalic acid, 
being a crystalline solid of constant composition and easily weighed, 
is chosen for the acid reagent. Its formula is H 2 C 2 4 .2H 2 0, with 
a molecular weight of 125.7. As there are 2 atoms of acid hydro- 
gen counted to make 125.7, the amount representing 1 atom of 
hydrogen would be one-half or 62.85. Then 62.85 § m - iri wa ter, to 
make 1000 c.c, will make the normal solution. If we want to repre- 
sent weak acidity, like that of the urine and gastric juice, one-tenth 
of 62.85 or 6.28 gm. per 1000 c.c. of solution is used, making the 

/N\ 
decinormal\ — \ solution of oxalic acid, each cubic centimeter of which 



© 



contains 0.00628 gm. of oxalic acid capable of neutralizing 0.0056 
gm. of potassium hydroxid or 0.004 g m - of sodium hydroxid. The 
basic or alkaline solution must contain the molecular weight in 
grams or the exact quantity of potassium hydroxid (56 gm.) or 
sodium hydroxid (40 gm.) necessary to hold the 1 gm. of hydrogen 
that would be taken from the normal acid solution. 

As the caustic alkalies contain varying amounts of water they 
should first be standardized by testing their concentration with 
the corresponding solution of oxalic acid. Thus: an excess, say 
60 gm. of potassium hydroxid or 50 gm. of sodium hydroxid, is 
dissolved in 900 c.c. of water and tested against 10 c.c. of normal 
oxalic acid solution placed in a beaker and reddened with litmus 
to ascertain the amount of alkali necessary to neutralize it. This 
amount multipled by 100 gives the number of cubic centimeters of 
alkaline solution containing the molecular weights — 56 gm. potas- 
sium hydroxid or 40 gm. of sodium hydroxid. If the amount be 
9.5, then 950 c.c. will contain the gram-molecule amounts of alkali, 
and 50 c.c. of water (enough to make 1000 c.c.) must be added. 1 

Equivalents of Acids and Alkalies. — The label of the bottle 
containing the normal solutions may then state that 1 c.c. of the 
contents (XaHO or KHO) is the equivalent of — 

Hydrochloric acid, HC1 0.03637 gm. 

Nitric acid. HN0 3 0.06289 " 

Sulphuric acid, H 2 S0 4 0.04891 " 

Oxalic acid, H 2 C 2 4 .2H 2 0.06285 " 

x The decinormal solution for urine testing can be made by placing 100 c.c. of 
the solution just described in a mixing bottle and adding 900 c.c. of water. Or the 
whole operation can be changed by dividing the weights named above by 10, so that 
at last we have 5.6 gm. of potassium hydroxid, or 4 gm. of sodium hydroxid, in 1000 
c.c. of water. 



126 



NON-METALS 



The label of the normal oxalic acid solution may state that 
i c.c. of the contents is equivalent to — 

Ammonia, NH 3 0.01701 gm. 

Sodium hydroxid, NaHO 0.040 " 

Potassium hydroxid, KHO « . . 0.056 " 

Volumetric Analysis. — If it be desired to determine the 
percentage of hydrogen chlorid dissolved in a sample of hydro- 
chloric acid, 3.63 gm. of the sample are weighed, put into the 
beaker, and tested by adding normal solution 
of potassium hydroxid to neutralization. If it 
require 10 c.c. of KHO, then the acid liquid 
is a 10 per cent, solution, HC1 (the acidum hy- 
drochloricum dilutum. — U. S. P.). If only 9 c.c. 
sufficed, then the sample was 9 per cent. HC1, 
and is not concentrated to the official standard. 
Volumetric analysis is performed very rapidly, 
and in most cases the result is more accurate 
than if obtained by the tedious operation of 
precipitation, filtration, drying, and weighing 
known as the gravimetric method. Unless the 
chemist has had much experience 
he will obtain more accurate re- 
sults by measuring quantities with 
a buret than by weighing them on 
a balance. This operation of 
measuring by volumetric analysis 
is called titration, from the French 
word titre, referring to the special 
label stating the standard strength 
of solution and its equivalents. 

Besides the reciprocal determi- 
nation of acids and alkalies, the 
other principal volumetric opera- 
tions are oxidation and reduction 
(using permanganate for oxidiz- 
ing and oxalic acid for reducing); 
precipitation (chlorids by silver 
nitrate); and iodimetry (reaction of iodin and hyposulphite). 
Method of Titration. — A definite amount of the substance to 
be examined is measured off in a graduated pipet (Fig. 38) and 
placed in a small beaker or porcelain capsule. A few drops of 
the color indicator is then added, so that the point of neutraliza- 
tion or end of the reaction can be accurately determined. Litmus 
has been mentioned as an indicator, but phenolphthalein (1 per 
cent, in dilute alcohol) is very sensitive, and may be used when 









cc 




cc 


t! 




. • 

-S-i 


t; 




P, 


fc 




4-S 


-#-' 




33; 


-S-» 

-5_U 

=_n 




-1_I4 


-=_U 




-=_« 


-=_» 




-=-* 


-=_IJ 




-S_1T 






-=_» 
-=_!» 


SB 

*2 






S M 




-=_« 


-S_2* 




iH 


K 




J=_B 








.=_» 




-=_» 


-S-Jl 




-S-J0 


-S-Jt 




*J* 


t: 




ft: 


-s-jr 




-=_tf 


S-S* 




5-» 


-s-*l 




-=_» 


-=_# 




^* 


-JL« 




-8-0 


-g-« 




-3_« 


.=_«» 




-=_« 


M-« 




i» 


-=_« 




-=_« 






ts 


t: 




t: 


-e_» 




.=_«• 


\ 








Fig. 38.— Pipet for 
measuring. 



Fig. 39. — Mohr's 
burets. 



DISSOCIATION I27 

neither ammonia nor bicarbonates are titrated. It is colorless in 
acid fluids, but reddens by alkaline hydroxids and carbonates, 
but not by bicarbonates (PL 6, Figs. A, A'). The reagent is 
measured in a Mohr's buret, a glass tube 1 to 2 cm. in diameter, 
graduated in cubic centimeters and tenths, and closed below 
by a tap (Fig. 39). When supported upright the lower end is 
a narrow-pointed jet, connected by a short joint of rubber tubing, 
closed by a spring pinch-cock. If the reagent be affected by 
the rubber, as in the case of silver nitrate or potassium perman- 
ganate, then a glass cock takes the place of the rubber and pinch- 
cock. The reagent for acidimetry, normal solution of sodium or 
potassium hydroxid, is poured into the buret until it rises above 
the zero mark and then, placing the bottle at the tap, the reagent 
is run out until the mark is reached; thus the tap and jet are 
filled. Placing the beaker to catch the outflow, the alkaline solu- 
tion is run into the mixture of acid liquid and indicator, which is 
constantly stirred until the end of the reaction is indicated by 
the change of color. 

Practical Application. — To determine the degree of acidity 
of urine in terms of oxalic acid place in a beaker 50 c.c. of the 
sample and a strip of red litmus-paper or 4 drops of a solution 
of phenolphthalein. Fill the buret with decinormal sodium 
hydroxid, 1 c.c. of which contains 0.004 g m - of NaHO, which 

N 
neutralizes 1 c.c. of — of oxalic acid, containing 0.0063 °f the 
10 

acid. Run in the alkaline solution till the red litmus turns blue 

(or if phenolphthalein were used, the colorless urine turns red), 

N 
indicating the end of the reaction. If 12.3 c.c. of — NaHO were 

used, then 12.3X0.0063 = 0.07749 acidity in the 50 c.c. of urine, 
equal to 0.15498 gm. oxalic acid in 100 c.c. of urine. 

Alkalimetry. — If the sample be alkaline urine, the degree of 
alkalinity is determined by placing decinormal acid in the buret, 
and tinting the urine with blue litmus or red phenolphthalein. 
If ammonia be the cause of the alkalinity, methyl orange is the 
best indicator. The acid is dropped into the urine until the end- 
point is shown by the color change. If the acid used number 
8.3 c.c, then 8.3X0.004 = 0.0332, the alkalinity of 50 c.c. of urine, 
equal to 0.0664 gm. of sodium hydroxid in 100 c.c. of urine. 

DISSOCIATION 

From the statements on p. 123 it is clear that the hydrogen 
of acids is not like other hydrogen, such as that of water; the 
hydroxyl of bases is different from the same group in other com- 



128 



NON-METALS 



pounds, such as in hydrogen peroxid. The chlorin of the solu- 
tion of common salt in precipitating the silver from the silver nitrate 
shows a property shared by other chlorids, but peculiar to chlorin 
in a salt formed by hydrochloric acid, not possessed by the chlorin 
in many others of its compounds. This property is independent of 
the nature of the metal in the chlorid. On the other hand, the 
metal of the solution of base or salt shows by its reactions that its 
properties do not depend upon the other components. This 
ability of each component to act by itself can be explained by the 
theory that in solution there is a detachment of the hydrogen 
and chlorin of hydrochloric acid; of the sodium and chlorin of 
common salt; of the hydroxyl and sodium of caustic soda. Strong 
confirmation of this view is obtained on consideration of the fol- 
lowing experiments: 

Electrolytic Dissociation. — If an electrolytic cell be made 
with two electrodes of platinum, connected with three or four 
battery couples having a galvanometer or an electric bell in the cir- 
cuit, we can test the conductivity of different solutions in the glass 
cell. If pure water be put in the cell it does 
not conduct the electric current; therefore, 
the bell does not ring nor the needle of the 
more sensitive galvanometer oscillate. If 
hydrochloric acid, common salt, or sodium 
hydroxid be added, the current flows and is 
announced by the ringing of the bell or the 
oscillation of the needle. If the experiment 
be made with hydrochloric acid in a vol- 
tameter (Fig. 40), it will be observed that 
while the current is conducted hydrogen gas 
escapes at the cathode (negative pole) and 
chlorin at the anode (positive pole). The 
cathode gas may be lighted at the tap; the 
anode gas bleaches a piece of wet litmus- 
paper. 1 

Electrolytes and Ions. — Substances 
which in solution conduct the current and 
are broken up by it are called electrolytes. 
The components into which they are decom- 
posed were called by Faraday ions (movers) 
(p. 50). The best electrolytes are those very acids, bases, and 
salts we have been studying. Close observation teaches us that 
there is a perfect correspondence between their conductivity and 
1 The best results are obtained by filling the voltameter with a mixture of one 
part of hydrochloric acid to six of a saturated solution of sodium chlorid. The 
chlorin does not appear as a free gas until the liquid at the positive end is saturated 
with it. 




Fig. 40. — Voltameter. 



DISSOCIATION I29 

their chemical activity. They are believed to conduct the electricity 
only by the free ions, those that seek the cathodes, like hydrogen 
and the metals, being called cations; those that go to the anode 
like chlorin and hydroxyl, anions. The cations are supposed 
to carry the positive electricity to the cathode, deliver their charge, 
and, uniting with like atoms, become molecules; the anions do 
the same work for the negative electricity and resume their ordinary 
form. Electrolytes behave as if their ions differed from the same 
elements or compounds in their ordinary state in being energized 
by electric charges which they are free to carry to the electrodes. 
This may be indicated by separating the symbols with a comma 
and writing above them the signs of positive and negative elec- 
tricity; or by using the round point for the cation, and the accent 
marks for the anions, as follows: 

+ — 
HC1 dissociates into H, CI or H', CI' 

NaHO " " Na, HO or Na', (HO)' 

NaCl " " Na, CI or Na', CI' 

H 2 SO, " " H, H, SO, or H\ H\ (S0 4 )". 

These are illustrations of the first mode of ion formation; i. e., by 
the molecules in solution breaking down directly into an equivalent 
number of anions and cations. 

The ion reaction between dilute hydrochloric acid and a weak 
solution of the base, sodium hydroxid, forming a salt, sodium 
chlorid and water, is shown in either of the following equations: 

H\C1' + Na',(HO)' = Na,Cl' + H 2 0, 

H, CI + Na, HO = Na, CI + H 2 0. 

The ions of hydroxyl and hydrogen unite and neutralize each 
other to form undissociated water, but the ions of sodium and 
chlorin retain their charge and their characteristic reactions. 

Definitions.— An acid is a compound of hydrogen, which 
parts with its hydrogen in exchange for a metal, forming a salt. 
It is acid because when dissolved it yields hydrogen as cation. 
If the anion is simple the acid is binary, as H*,C1', if it is complex 
the acid is ternary, as H',H,(S0 4 )' r . 

A base is a compound of hydroxyl which neutralizes an acid 
forming a salt and water. It is basic because when dissolved it 
yields hydroxyl as anion. The cation is usually a simple metal. 
Eases are all ternary, as NaHO. 



130 NON-METALS 

A salt is a compound formed by the action of an acid upon a base 
or a metal. It is a compound of the anion of an acid with the 
cation of a base. 

The substitution of a metal for the hydrogen of an acid is rep- 
resented in the following equation: 

Zn + H*, CI' + H-, CI' = Zn",Cl', CI' + H 2 

Atom. Ions. Ions. Molecule. 

The divalent zinc (p. 114) takes two positive charges from the 
monovalent hydrogen ions, becoming itself an ion carrying two 
charges, while the hydrogen ions having lost their charge, form 
the neutral molecule. 

The Ions of Indicators. — The characteristic changes in litmus 
and phenolphthalein caused by acids and alkalies find an expla- 
nation in the theory of a difference of color between the molecule 
of the indicator and its ion. Red is the color of the acidic mole- 
cule of litmus, which, being weak, is scarcely dissociable. When 
the acid litmus is neutralized by an alkali, a salt is formed and 
the blue anion of litmus is set free. Phenolphthalein is also 
weakly acidic and, therefore, not dissociable. In this molecular 
state it is colorless when it is added to water or to the aqueous 
solution of a strong acid. In the process of titration a strong 
base is added until the free acid is neutralized. At this point one 
more drop of the alkali unites with the acidic phenolphthalein 
and forms a dissociated salt, of which the complex organic anion 
has a red color. 

Hydrolysis. — Weak acids and weak bases do not give a sharp 
change in color because, when dissolved, the salt of a weak base, 
like ammonium chlorid, or of a weak acid, like sodium hypo- 
chlorite, does not break up into the cation of the metal and the 
anion of the other component, as does sodium chlorid, but into 
the corresponding free acid and free base. To do this the water 
itself breaks up very slightly into H*, (HO)', yielding, on the one 
hand, H* to make the acid HCIO, and on the other, (HO)', which 
always gives the alkaline reaction. The salt is said to be hy- 
drolyzed because there is decomposition through the agency of 
water. The solution behaves as if the acid and base had not 
neutralized each other, each giving its own reaction. Weak bases 
do not give a sharp reaction to litmus or phenolphthalein, as they 
do not suddenly free the litmus in a deep blue, and the other 
indicator in a marked red color, but form hydrolyzed salts with 
the indicators, producing gradual changes of tints. Hence, in 
titrating for weak acids, litmus and a strong base, sodium or 
potassium hydroxid, are used. In such a case, if phenolphthalein 
be used and the weak acids — carbonic, phosphoric, or carbolic — 
be titrated, a slight change of tint begins and deepens slowly before 



DISSOCIATION 131 

the acid has been neutralized. Nor does it act sharply in the 
opposite case when ammonia is titrated, because that is a weak 
base permitting hydrolysis. The practical conclusions are: (1) 
For weak acids a weak acidic indicator, like litmus, may be used, 
but it must be titrated with a strong base. (2) For weak bases, 
like ammonia, a strongly acidic indicator, like methyl orange, is 
required, and the titrating reagent must be a strong acid. In the 
acidic molecule methyl orange is red, but converted by a base into 
a dissociated salt, its anion is yellow. 

Ionization by Fusion. — As the temperature rises, many 
solid substances increase in electric conductivity and when melted 
become so highly ionized as to conduct freely and undergo elec- 
trolysis. Many metals are now separated from their fused com- 
pounds by electricity. 

Nomenclature of Ions. — For convenience of description of the 
reactions of ions, special terms have been devised, based on a 
system. The ion of hydrogen is called hydrion, and other cations 
have their names likewise formed from the stem of the scientific 
name of the metals and the suffix -ion. The ion of hydroxyl is 
called hydroxidion, and other anions are named likewise according 
to the salt, those ending in -id or -ide having the suffix changed 
to -idion. For example: the chlorin ion is called chloridion. 
When the name of the salt ends in -ate, the corresponding ion has 
the suffix -anion. For example: in potassium chlorate the two 
ions are called potassion, K*, and chloranion, (ClOg)'; the anion 
of carbonates, (C0 3 )," is carbanion. If the name of a salt end 
in -ite, the termination of the name of its anion is -osion. For 
instance: in the salt sodium hypochlorite we have sodion, Na*, 
and hypochlorosion, (CIO)'. 

Summary of the Ion Theory. — It has been shown that 
when hydrogen chlorid is dissolved in water the new powers of 
hydrochloric acid are developed, the elements showing a different 
energy from that displayed by them in the dry gaseous state. 
These new powers in HC1 may be accounted for upon the theory 
that the ionized elements receive a new charge of electricity when 
the molecules are broken up, and possess a much greater freedom 
of action than did the atoms in the molecule. The current con- 
ducted by an electrolyte is transported by the simultaneous move- 
ment of the component ions. The quantity carried is propor- 
tional to the quantities and the valence of the ions. Chemical 
diversity is regulated by electric relations. Electric conductivity 
of a solution should be proportional to its number of free ions; 
and vice versa, the number of free ions can be estimated by meas- 
uring the conductivity. It would follow also that the total number 
of particles — that is, molecules of NaCl and ions of Na* and CF 



132 NON-METALS 

in a normal solution of common salt would be larger than if none 
of the molecules had been dissociated. As the molecules in a 
normal solution of a non-electrolyte, like sugar, are not disso- 
ciated, they do not form so many particles as do the electrolytes. 

In previous sections (pp. 37 and 96) it has been stated that 
acids, bases, and salts in aqueous solution have more effect upon 
the freezing-point, the boiling-point, and the osmotic pressure than 
have sugar, glycerin, urea, and other non-electrolytes when dis- 
solved in equivalent amounts. These and other physical abnor- 
malities are correlated with the peculiar chemical and electrolytic 
behavior of electrolytes. The changes of energy in dissolving 
a substance correspond to the number of particles dissolved; and 
the number of free ions in solution is indicated by the electric 
conductivity. From this relative number of free ions we estimate 
the total relative number of all particles, molecules plus ions, and 
with this total calculate the lowering of the freezing-point and 
elevation of the boiling-point. On comparing the calculated 
results with the observed facts so close a mathematic agreement 
is found that we can not escape the conclusion that the theory of 
ion dissociation is well founded, for it has harmonized phenomena 
widely at variance with one another and has furnished to practical 
science working principles of real value. The liquid in which 
the life functions of plants and animals are performed is invariably 
a dilute electrolyte with a high degree of dissociation of ions. 
By applying the new conception to the sciences growing out of 
chemistry it has made intelligible many hitherto unexplained facts 
in analysis, in color-changes of indicators, in physiology, in bac- 
teriology, and in toxicology. 

Dissociants. — Of the whole number of molecules dissolved, 
only a fraction are usually dissociated. The number in this 
fraction depends on the nature of the solvent and the concentration. 
All liquids that are solvents of acids, bases, and salts will also 
dissociate their molecules to some degree. By using the methods 
above mentioned for measuring dissociation — that is, by freezing- 
point, boiling-point, and electric conductivity — it is ascertained 
that water has more dissociating power than any other liquid. 
Methyl alcohol has from one-half to two-thirds the dissociating 
power of water, ethyl alcohol not more than half that of methyl 
alcohol, or about one-fourth that of water. The hydrocarbons, 
ethers, aldehyds, esters, and other derivatives are weak dissociants. 

Effect of Solution. — Mention has been made of the fact that 
when tested apart from a solvent acting as dissociant, dry chlorin 
does not bleach nor act on sodium, and dry hydrogen chlorid does 
not redden litmus nor liberate hydrogen in the presence of metals. 
Other experiments concur with these to show that molecules, when 



DISSOCIATION I33 

whole, act very little, if at all; it is only as they are broken up into 
ions that their chemical energies come into play. In the elec- 
trolytes, which react with promptness, there are many ions; in 
non-electrolytes, such as the organic bodies, sugar and albumin, 
there are few ions, and their reactions are much slower. 

Effect of Concentration. — The degree of dissociation or the 
fractional number of ions depends mainly on the concentration. 
As the relative conducting power of electrolytes rises with the dilu- 
tion up to a certain limit, it is assumed that when this highest 
point is reached dissociation is complete. When the strong acids, 
bases, and salts are in very dilute solution it is highly probable 
that the relatively few molecules have all been dissociated. It is 
discovered that at this point of highest conductivity the acids, 
bases, and salts are most active chemically — that is to say, that 

the millenormal I ) solution of HC1 has more than ttoo the 



\iooo/ 



activity of the normal (N) solution. 

Strength of Acids. — As stated above, experiment shows that 
the relative electric conductivities of acids vary as do their chem- 
ical activities. When hydrochloric acid has been diluted until it 

N 

is a solution, the high conductivity makes it probable that 

1000 

its molecules have nearly all been separated into free ions, but 

the solution of acetic acid has not reached its highest con- 

1000 

ductivity, and is believed, therefore, to have but few dissociated 

/N\ 
ions. When zinc is put into equal volumes of decinormal ( — 1 

hydrochloric and acetic acids separately, they will each dissolve 
the same weight of metal because each contains the same quan- 
tity of acid hydrogen. But the velocity of their action is very 
different, hydrochloric acid finishing its work much sooner; hence 
it is said to be more active. Nearly all the hydrogen of hydro- 
chloric acid is at once available, little of it being held in molecules, 
but with acetic acid some of the hydrogen ions must escape before 
the many undissociated molecules dissociate into active ions. In 
other words, the strongest acid chemically is the one that is most 
dissociated, having the highest proportion of free hydrogen ions. 
The degree of dissociation of the following acids is about the same 
as that of neutral salt; they are very active and are called the strong 
acids, i. <?., hydrochloric, hydriodic, hydrobromic, chloric, per- 
chloric, sulphuric, polythionic, and nitric. Usually sulphurous, 
phosphoric, and acetic acids are not dissociated beyond 10 per 
cent, and are called moderately strong. A dissociation of less 



134 



NON-METALS 



than i per cent, characterizes as weak the acids sulphydric, carbonic, 
hydrocyanic, silicic, and boric. 

Analysis. — The first act in the analysis of salts is dissolving 
them in water. In solution they dissociate into their components, 
the metal and the residue derived from the acid; these have indi- 
vidual reaction. As stated above, the chlorin in chlorids has 
a peculiar reaction with silver nitrate irrespective of the metal with 
which it is united, and different from that in the chlorates. So it 
is with iodids, sulphates, and other acidulous factors of salts. 
The metal in its turn is sought independently, regardless of the 
other constituents. The salts formed by copper with the different 
acids will yield to hydrogen sulphid the same black precipitate, 
The first step of dissolving the salt separated its component ions 
to such a degree that the behavior of each became independent 
of the other. 

Mixed Solutions. — When solutions of acids, bases, and salts 
are mixed without precipitation the free ions of all of them are 
contained in the mixture and can be identified by individual tests; 
no matter how they were arranged in the original salt. Thus: 
When equivalent amounts of sodium chlorid, NaCl, and potas- 
sium iodid, KI, are mixed in solution they evolve no heat and give 
exactly the same reactions as does a mixture of potassium chlorid, 
KC1, and sodium iodid, Nal. When some of the mixed ions can 
unite to form an insoluble compound they do so with heat changes, 
forming a precipitate. Thus: mixed solutions of potassium iodid, 
KI, and lead nitrate, Pb(NO s ) 2 , develop heat and separate out the 
undissociated solid lead iodid, Pbl 2 . 

Ions of Consummated Reactions. — The reaction between two 
active substances begins as soon as they are brought together. 
The initial velocity depends on the temperature and the concen- 
tration (mass) of the solutions. This movement gradually declines 
until the material and the products reach a definite concentration, 
when a condition of equilibrium is established between the direct 
and the reverse reactions (p. 83). In an operation where one of 
the reacting substances escapes so fast that its acting mass is never 
a factor inducing the state of equilibrium, the direct action goes on 
to completion, thus: 

1. The gas hydrogen is set free from an acid by the substitution 
of a metal (p. 80). 

2. A volatile product is distilled away by heat as in the prepa- 
ration of hydrochloric acid (p. 136). 

3. An insoluble product is precipitated by the combination of 
dissolved ions into molecules, as when silver nitrate is acted upon 
by a chlorid: 

Ag-,(NO s )' + Na',Cl' = AgCl + Na', (NO,)'. 



HYDROCHLORIC ACID 135 

4. The ions of a metal in solution are deposited as atoms by 
electric action, as in plating with copper. 

Cu"(S0 4 )" + H 2 = Cu + H- 2 (S0 4 )" + O. 

Applications in Toxicology. — The poisonous properties of 
many compounds are not the sum of those of the elements com- 
posing them. In this matter the compound does not act as a whole, 
nor do the elements as individuals, unless they have been ionized. 
A solution of potassium cyanid is very poisonous, but one of potas- 
sium ferrocyanid is not, and yet cyanogen is in both. In the 
first-named the poison exists as cyanidion (CN)', formed when 
the salt is first dissolved. In the second-named, which contains 
iron and cyanogen, there is no exhibition of the chemical or toxic 
reactions of either, because the cation is potassion, and the anion 
is more complex than ferrion Fe* or cyanidion (CN)', being 
[Fe(CN) 6 ] //// , ferrocyanidion, entirely devoid of poisonous prop- 
erties. 

Silver salts are reduced in toxic effect by the addition of sodium 
thiosulphate ; argention, Ag # , is lost in a new complexion, (AgS 2 3 )', 
which is non-toxic, as it does not exert the same activity as Ag\ 

The caustic alkalies disorganize and dissolve tissue by virtue 
of the hydroxidion (HO)' and not because of the metal, for sodium 
chlorid contains the metal, but is not poisonous. Hydroxyl 
undissociated is not poisonous, for if it were, alcohol in aqueous 
solution would corrode, as it contains that group, though not in 
the state of ion. 

The sulphates of potassium, sodium, and magnesium in con- 
centrated solution are active cathartics. They have in common 
the group (S0 4 )' sulphanion, and they are all irritants. It is a 
fair presumption that the metal cations take no part here; their 
local effects are indifferent in their other compounds. The bowel 
irritation caused by the sulphates is proportional to the relative 
weight of sulphanion, which is greatest in potassium sulphate, and 
least in the magnesium salt. 

HYDROCHLORIC ACID (Acid Muriatic) 
Formula, HC1. Molecular weight, 36.45. 

Preparation. — The commercial muriatic acid not infrequently 
contains a trace of arsenic. As it is easier to obtain arsenic- 
free sulphuric acid, the analyst sometimes makes for himself the 
hydrochloric acid he intends to use in detecting arsenic. Fifty 
grams of pure common salt are put into a flask or retort and 
then is added through a funnel tube dilute sulphuric acid, which 
has been mixed in advance and allowed to cool. To make dilute 



136 



NON-METALS 



sulphuric acid 30 c.c. of the pure acid is diluted with 10 c.c. of 
water. If gas does not immediately escape, gentle heat may be 
applied (Fig. 41). The gas is passed into a suitable wash-bottle 
in order to charge the distilled water it contains. 



NaCl + H 2 S0 4 



Sodium chlorid. 



Sulphuric acid. 



; HC1 + HNaS0 4 

Acid hydrochloric. Sodium bisulphate. 



This is a reversible equation, and in the cold an equilibrium is set 
up among the four substances dependent on the quantities. When 
part of the volatile HC1 escapes by heat the equilibrium is destroyed 
and action goes on to make fresh HC1. 

Official Preparations. — Acidum hydrochloricum contains 31.9 
per cent, by weight of anhydrous HC1. Dose: 3 to 10 TTL 

(0.20-0.66 c.c), well diluted; in- 
^3 compatible with alkalies, chlo- 

rates, chromates, salts of silver, 
J mercury, and lead, oxids, perman- 

ganates, tartar emetic. Acidum hy- 
drochloricum dilutum, contains 10 
per cent, by weight of anhydrous 
HC1. Dose: 10 to 30 TTL (0.66- 
2 c.c), well diluted with sweetened 
water. 

Properties. — Commercial hydro- 
chloric, or muriatic acid is a trans- 
parent, yellow, corrosive liquid. Its 
strength or percentage of pure acid 
gas is approximately the product of 
200 and the decimals of the specific 
gravity. Thus, a sample of a specific gravity of 1.15 should contain 
30 per cent. HC1 (200X0.15). 

The chemically pure acid is colorless, the yellow color of the 
commercial article being due to a trace of iron from the appa- 
ratus used in its manufacture. A more important contaminant is 
arsenic, taken from the sulphuric acid used in generating it. The 
average amount of this impurity is 0.25 per cent, of arsenic tri- 
oxid. The pure acid liquid of the U. S. Pharmacopoeia is sour, 
of pungent odor, and contains 450 volumes of gas dissolved in 1 
volume of water, which increases more than one-third in bulk. 

On exposure to the air the strong acid gives off visible fumes, 
due to the union and condensation of the invisible gas with the 
aqueous vapor of the air. The fumes have a pungent odor, an 
acid taste, are irrespirable, are one-fourth heavier than the air, and 
when allowed to blend with the fumes of ammonia form dense 
white clouds of ammonium chlorid. It acts upon metals and 




Fig. 41. — Charging water with soluble 
gas. 



HYDROCHLORIC ACID 



*37 



bases, forming chlorids. The acid dissolves most of the metals, 
but not gold and platinum, and when heated with manganese 
dioxid, chlorin is set free. It is the natural acid of the gastric 
juice, and is used with pepsin as an aid to .digestion. It is em- 
ployed in chemical analysis as a group-reagent, from its having 
the property of precipitating mercury (from mercurous salts), 
lead, and silver. 

The precipitation of silver salts occurs according to the fol- 
lowing equation: 

Ag-,(N0 3 )' + H-,C1' = AgCl + H./,(N0 3 )' 

Silver nitrate Silver chlorid Acid nitric 

ions. molecules. ions. 

When the ions of the first half of an equation can unite to form 
an insoluble molecule, the union occurs and a precipitate falls. 
This precipitate, AgCl, is soluble in ammonium hydroxid, but 
insoluble in nitric acid. A similar precipitate of mercurous chlorid 
turns black with ammonium hydroxid, while that of lead chlorid 
under the same conditions remains white and undissolved. 

Toxicology.— The Corrosive Acids.— The mineral acids: 
hydrochloric, sulphuric, and nitric, turn red the vegetable blue 
colors, and change the hue of dyed clothing mostly to red or yellow, 
and also injure the texture. When concentrated, they rapidly 
destroy organic substances, and on the living body cause the most 
violent pain. They are simple corrosives, causing well-marked 
symptoms, due to their action on the part to which they are ap- 
plied, complicated by the effects of shock upon the system at large. 

Hydrochloric acid is very corrosive, but not so severe in its 
local action as either sulphuric or nitric acid. Owing to its vol- 
atility there is great liability of acute laryngeal inflammation from 
its irritating fumes, although the liquid itself may not enter the 
glottis. The lips, tongue, and throat are first white, but later 
become brown and rotten. There are instant pain in the mouth, 
throat, and abdomen, difficult swallowing, husky voice, spas- 
modic breathing, retching and vomiting, feeble pulse, and general 
weakness, the mind remaining clear to the last. If the patient 
survive these acute symptoms, he remains subject to stricture of 
the gullet or pylorus, with loss of function of the stomach. 

Fatal Dose. — A few drops may prove fatal if they enter the 
larynx. By rapid swallowing and quick transmission to the 
stomach death may follow upon a fluidram dose. 

Fatal Period. — From the acute effects death may ensue in 
fifteen hours or even in two hours, but, as a rule, the duration 
of life will be twenty-four hours. The secondary consequences 
are productive of a poor vitality for a variable period. One case 



I38 NON-METALS 

has been reported of death from stricture of the pylorus after four 
months. 

Treatment. — The remedial measures are the same for hydro- 
chloric as for sulphuric and nitric acids. 

The antidotes owe their power to chemical neutralization, 
changing the fiery acid to harmless neutral salts. 

Calcined magnesia, given freely, suspended in water or milk, is 
a perfect antidote. When it cannot be had at once, as prompt- 
ness is all-important, "prepared chalk," "whiting" used to polish 
silver, plaster scraped from the wall, soapsuds, or largely diluted 
alkalies, such as sodium carbonate ("washing-soda"), sodium 
bicarbonate ("bread or baking-soda," "saleratus"), sodium hy- 
droxid ("concentrated lye"), or the corresponding compounds 
of potassium, should be given in milk or water. It rarely happens 
that the antidote is given soon enough to prevent the energetic 
action of the poison, and even after thorough neutralization 
it would be best to give milk and very dilute alkaline solutions 
for some hours. As the tube of the stomach-pump or the siphon 
impinging upon the softened structures may do irreparable harm, 
it must not be used, though later the esophageal stricture may 
call for careful treatment by dilator and tubes. 

Postmortem Appearances. —The pathologic changes found 
after death from hydrochloric acid cannot be distinguished from 
those induced by sulphuric acid, except by the local effects on 
lips and face. 

Hydrochloric acid leaves no permanent stain nor erosion 
externally, while sulphuric acid discolors and nitric acid turns yel- 
low. Internally, we find the signs of intense inflammation, with 
a shriveled and worm-eaten condition of the mucous membrane, 
which has a white or brownish color. The appearances due to 
sulphuric acid are the same, except that the destruction of tissue 
is greater, but the yellow marks of nitric acid are always charac- 
teristic. 

Tests. — The free acid gives the acid reaction to litmus. A 
glass stopper or rod wet with it and held near an open bottle of 
ammonia-water smokes with the white clouds of ammonium 
chlorid. Poured upon zinc, it evolves hydrogen gas; if heated 
with manganese dioxid, it yields greenish-yellow chlorin gas which 
bleaches a piece of moist litmus-paper suspended in the vapor. 

Silver Nitrate Test. — The chief test for chlorids serves equally 
for this acid — that is, silver nitrate — which gives a heavy, curdy, 
white precipitate of silver chlorid, soluble in ammonium hydroxid, 
but insoluble in nitric acid. 

As proof of the presence of a free mineral acid, litmus will not 
serve, as it is affected by acid salts and by the organic acid of 



COMPOUNDS OF CHLORIX CONTAINING OXYGEX 139 

digestion. Resort can be had to paper colored by certain anilin 
dyes which react to minute quantities of free mineral acids, but 
not in the same way to the organic acids nor to acid salts. A drop 
of the gastric contents containing a free mineral acid put on 
Congo-red paper leaves a dark-blue spot (PL 5, Figs. 2-4) or 
if touched to Topfer's vellow reagent turns it red (p. 549, Plate 6, 
Fig. C). 

Detection. — Very little help is derived from a study of the 
stains on clothing. At first a reddish spot appears. On some 
black dyes the color is greenish, but owing to the volatility of the 
acid, the spots are evanescent. They are not moist, charred, nor 
rotten, as they are from sulphuric acid, nor are they yellow, as from 
nitric acid. After a few days the moistened cloth will not affect 
litmus, but if boiled in water, silver nitrate will show more chlorids 
in it than in the untouched cloth. 

In the examination of the vomited matters we are liable to a 
fallacy from the natural presence of 0.2 per cent, of hydrochloric 
acid in the gastric juice, and from the chlorin in the alkaline 
chlorids of food. 

If the material be strongly acid, sulphuric acid must first be 
tested for and excluded. Distillation will then collect the volatile 
hydrochloric acid, which can be estimated by titration with sodium 
hydroxid. 

To determine both free acid and the combined chlorids, first 
make a filtered watery extract and divide it into two equal parts. 
One of these is neutralized by adding an excess of sodium car- 
bonate, which fixes the volatile free acid. Both are evaporated 
to dryness, the unneutralized portion losing all its free acid. Both 
residues are redissolved in water and are treated separately with 
acid solution of silver nitrate. If the neutralized portion show 
more chlorids than the other, the difference equals the amount 
of free hydrochloric acid originally present in each portion. In 
this analysis 100 parts of silver chlorid precipitated represent 
about 80 parts of hydrochloric acid (specific gravity 1.15) or 25.43 
parts of the anhydrous acid. 

COMPOUNDS OF CHLORIN CONTAINING OXYGEN 

Chlorin and oxygen form two compounds — chlorin monoxid, 
C1 2 0, and chlorin tetroxid, C1 2 4 — both of which are unstable 
and at times violently explosive. They are present dissolved with 
free chlorin in liquor chlori compositus (p. 120). They have no 
special uses in medicine or in the arts of everyday life. 

An acid formed with hydrogen and without oxygen is known 
as a hydracid. To this class belong HC1, HBr, and HI. When 
oxygen is a constituent, the acid is termed an oxyacid. There 



140 NON-METALS 

are many representatives of this class, and among them are the 
four oxyacids of chlorin, which illustrate well the law of multiple 
proportion, but are quite unstable, and of little practical impor- 
tance: 

Hypochlorous acid HCIO 

Chlorous acid HC10 2 

Chloric acid HC10 3 

Perchloric acid HC10 4 

The nomenclature of these acids is governed by the proportion 
of oxygen they contain. If there be but one acid to an element, 
such as the hydracid HC1, the termination -ic is used, and its salts 
end in -ate. If there be two oxyacids, the one containing the 
smaller proportion of oxygen has the suffix -ous, as chlorous, 
HC10 2 ; the other -ic as chloric, HC10 3 . The names of salts of 
acids ending in -ous are formed by adding to the stem the suffix 
-ite. When an element forms more than two oxyacids, the prefix 
hypo- is given to the acid having less oxygen than the -ous acid, 
as hypochlorous; and the prefix per- to the acid having more than 
the -ic acid, as perchloric. In the above list will be found four 
acids named according to this system, only two of which, however, 
are of interest to us — hypochlorous and chloric. 

Hypochlorous Acid.— Calx Chlorinata. — When slaked lime 
is exposed to the action of chlorin gas for about sixteen hours, 
it takes up the chlorin and forms the commercial product known 
as chlorid of lime, or bleaching powder, the official name being calx 
chlorinata in U. S. P. Not markedly deliquescent, it probably 
does not contain calcium chlorid, for that compound is deliquescent 
to a high degree. The composition of calx chlorinata is repre- 

Cl 
sented by the formula Ca(C10)Cl, or Ca<C rlr .; and its manufac- 
ture by the equation: 

Ca(HO) 2 + Cl 2 = Ca(C10)Cl + H 2 0. 

Lime. Calx chlorinata. 

Treated with water, calx chlorinata dissolves, changing into 
calcium chlorid and calcium hypochlorite: 

2 Ca(C10)Cl = CaCl 2 + Ca(C10) 2 . 

The bleaching action of calx chlorinata is demonstrable by 
smearing a printed page with writing ink, dipping the page into 
a dilute solution of calx chlorinata, and while wet transferring it 
to weak hydrochloric acid. Any textile fabric so treated will 
have nascent oxygen and chlorin set free in its meshes. The 
carbon of the printers' ink will not be affected. 



COMPOUNDS OF CHLORIX CONTAINING OXYGEN 141 

Ca(C10) 2 + 2HCI = CaCl 2 + H 2 + Cl 2 + O. 

Calcium Calcium Xascent 

hypochlorite. chloric!. oxygen. 

A solution of calx chlorinata, 1 pound to the gallon of water, 
represents in a more stable form all the disinfecting powers of 
aqua clilori, and is extensively used as a deodorizer and germicide. 
Exposed to the air it evolves chlorin spontaneously. 

When calcium hypochlorite is acted upon by very dilute nitric 
acid and the product distilled, dilute hypochlorous acid is ob- 
tained. 

Ca(C10) 2 + 2HNO3 = Ca(NO s ) 2 + 2HCIO 

Calcium Nitric Calcium Hypochlorous 

hypochlorite. acid. nitrate. acid. 

Properties. — Hypochlorous acid has not yet been formed abso- 
lutely dry. In aqueous solution it has the strong smell of chlorin, 
but not the greenish hue of chlorin water. It does not keep well, 
soon breaking up into oxygen and hydrochloric acid. As it 
yields a ready supply of active oxygen it has the same bleaching 
and germicidal powers possessed by chlorin-water. 

HCIO = O + HC1. 

Tests. — Owing to the constant presence of some hydrochloric 
acid it yields a white precipitate with silver nitrate. It decolorizes 
litmus and indigo in solutions. 

Sodium hypochlorite, NaCIO, is known only in the official 
liquor soda chlorinake, Labarraque's fluid, which contains NaCl 
-f- NaCIO, and is prepared by decomposing solution of calx chlo- 
rinata by sodium carbonate, or by passing chlorin into a solution 
of caustic soda: 2NaHO + 2Cl = NaCl + NaC10 + H 2 0. It is more 
permanent than chlorin-water, but undergoes a change in time, 
losing its chlorin smell and bleaching power and the property 
of yielding chlorin when treated with dilute hydrochloric acid, 
due to the loss of its hypochlorite. On evaporation sodium 
chlorid is obtained, and another salt having the composition 
NaC10 3 , called sodium chlorate: 

3 NaC10 = 2 XaCl + NaC10 3 

Sodium hypochlorite. Sodium chlorate. 

If caustic potash, KHO, had been used, then potassium hypo- 
chlorite would have formed, changing to potassium chlorate, 
KCIO3, a well-known salt already referred to as a source of oxygen. 
By electrolysis of a solution of this salt, potassion K* moves to the 
cathode and chloranion (C10 3 )' to the anode. As the chlorin is 
here part of a complex anion it is not surprising that this salt does 
not precipitate silver chlorid from solution of silver nitrate (p. 137). 



142 NON-METALS 



OTHER HALOGENS 

BROMIN (Bromurn) 

Symbol, Br. Atomic weight, 79.96. 

Occurrence. — Though met in smaller quantities than chlorin, 
which it closely resembles, bromin is widely distributed in nature. 
In the residues of evaporation of sea-water bromin compounds 
of sodium and magnesium are found, and from these the element, 
is liberated. 

Preparation. — The reactions by which bromin is made are 
parallel to those used for chlorin. By electrolysis of bromids the 
bromidion moves to the anode and separates as free bromin, the 
metal going to the cathode. By another method the bromids in 
sea salt are in one operation converted to hydrobromic acid, and 
this, oxidized by manganese dioxid, loses its hydrogen, leaving free 
bromin. 

2NaBr + H 2 S0 4 = Na 2 S0 4 + 2HBr 

Sodium broraid. Sodium sulphate. Hydrobromic acid. 

2 HBr + O = H 2 + Br 2 . 

This process is facilitated by the free chlorin formed from the* 
chlorids present in the salt; or chlorin may be obtained outside 
and passed into the brine. It decomposes the bromids and the 
bromin distils over. 

Properties. — Physical. — Bromin is a dark, reddish-brown 
liquid, opaque in thick layers, with a specific gravity of 3.1. At 
ordinary temperatures it vaporizes in red fumes of an unpleasant 
odor and is highly irritating to the mucous membrane of the nose 
and air-passages. It should be held at arm's length in handling. 
It boils at 6o° C. (140 F.) and solidifies at -7 C. (19 F.),. 
forming a dark crystal. It is soluble in alcohol, ether, and chlo- 
roform. At room temperature it dissolves 3 per cent, in water,, 
making a brown-yellow liquid with the properties of bromin. This 
solution is used as a reagent under the name of bromin- water. 
Exposed to light, bromin-water decomposes, forming hydrobromic 
acid. When the water already contains a bromid in solution, the 
bromin dissolves in larger amount, forming compounds that 
readily decompose and behave in a manner similar to free bromin. 
There is no more free bromin in solution than would be the case 
if water alone were the solvent, but the salt holds the bromin as 
the brown-colored ion, Br' 3 (tribromidiori). In any reaction the 
bromid-salt solution yields fresh bromin to the water as fast as the 



BROMIN 143 

free bromin is removed. The ion Br' 3 splits into Br' + Br 2 , which 
is to say, the tribromidion yields bromidion and neutral bromin. 

Chemical. — The behavior of bromin is similar to that of chlorin, 
but its activity is less. It is a monad, combines with many ele- 
ments directly, and unites with arsenic with so much vidity as to 
evolve heat and light. If powdered magnesium be shaken with 
bromin-water the color disappears, and after filtering off the metal 
a solution of (MgBr 2 ) magnesium bromid remains. If this is 
decomposed in an electrolytic cell yellowish bromin is liberated at 
the anode, while at the cathode white magnesium hydroxid, 
Mg(HO) 2 and bubbles of hydrogen appear. The free magnesium 
has taken hydroxyl from water and set free the hydrogen. 

Medical Uses. — Bromin has been given internally in doses of 
1 to 3 Tit (0.06-0.18 ex.), well diluted; externally as an antiseptic 
in 1 per cent, lotions, or as caustic, used pure or with equal parts of 
alcohol. The alkaline bromids are given internally as sedatives, 
hypnotics, and antispasmodics. It is incompatible with caustic 
alkalies, arsenites, ferrous salts, hypophosphites, hydriodic acid, 
and mercurous salts. 

Toxicology. — Symptoms. — Bromin vapor when inhaled causes 
symptoms of violent catarrhal inflammation of the air-passages, 
with cough, constriction of the chest, and hemoptysis. It acts 
vigorously as a caustic on organic matter, producing, when swal- 
lowed, pain in the mouth, throat, and stomach, with eructation 
of the peculiar offensive vapor. Its powerful local action may 
bring on collapse in a few hours. 

Fatal Dose and Period. — Very few cases of death have been 
reported. One was caused by 1 oz. of bromin. In another fatal 
case a child of ten took what was calculated to be about 2 gr. of 
bromin. Fatal collapse has come on within seven hours. 

Treatment. — If it has been swallowed, complete evacuation 
must be secured by emetics (5 Vf[ of a 2 per cent, solution of apo- 
morphin hydrochlorate) and the stomach-pump. The chemical 
antidotes are protectives, such as raw eggs, mucilaginous drinks 
made from starch, arrow-root, barley, rice, flour, or meal. If 
bromin has been inhaled, ammonia vapor and steam must be 
inhaled as antidotes. For depression whisky may be given. 

Postmortem Appearances. — A dark-brown stain marks the 
point of local action; the mucous membrane is inflamed, softened, 
loosened, or even corroded. 

Detection. — The element may be identified by its color and 
odor. If it be present as bromidion in a bromid, the bromin 
must be freed by adding a little chlorin-water. The chlorin 
becomes chloridion and the bromidion changes to neutral bromin 
with its characteristic brownish color, K'Br'+ Cl= K'Cl' + Br. 



144 NON-METALS 

When bromin-water is shaken with chloroform, the latter takes up 
the bromin and separates it in a brownish-yellow layer. Starch- 
water forms the bromid of starch, which is of a deep yelllow color. 

"Bromism." — This name has been given to the poisonous 
effects of long-continued dosing with bromids. The symptoms 
are the fetid odor of bromin on the breath, mental dulness, ner- 
vous depression, muscular weakness, absence of sexual feeling, 
eruptions of acne, bullae, and pustules. When pushed to the 
extreme, the bromids have caused exhaustion and fatal heart 
failure. 

Hydrogen bromid, HBr, is a colorless gas readily soluble in 
water, forming acidum hydrobromicum dilutum (U. S. P.), which 
is a io-per cent, solution of hydrogen bromid, resembling hydro- 
chloric acid in chemical properties, but medically having the 
sedative action of bromids. It is given to allay cough in doses 
of 30 to 90 Til (1.90-5.70 c.c.) in sweetened water. 

The bromids in general are formed like the chlorids and 
have similar properties. 

Like the chlorids, they are quite soluble, except the bromid 
of silver, the mercurous bromid, and the lead salt, which are 
almost insoluble. The silver bromid is insoluble in nitric acid 
and sparingly soluble in ammonium hydroxid. 

The reaction with silver nitrate is as follows: 

K',Br' + Ag-, (NO s )' = K',(N0 3 )' + AgBr. 

The precipitate AgBr does not form unless the bromin is dis- 
sociated as bromidion. Thus in ethyl bromid, C 2 H 5 Br, a non- 
electrolyte, the bromin is not ionized and there is no reaction with 
the silver ion. 

Oxyacids. — Three oxyacids are known and they are more 
permanent than the corresponding compounds of chlorin. They 
are hypobromous acid, HBrO; bromic acid, HBrO s ; and per- 
bromic acid, HBr0 4 . 

IODIN (Iodum) 
Symbol, I. Atomic weight, 126.85. 

Occurrence. — In nature iodin is found combined with potas- 
sium, sodium, calcium, and magnesium in sea-water, in sea ani- 
mals, and sea plants. 

Preparation. — The ashes of the seaweed called kelp are 
extracted with water, and by evaporation the other salts crystal- 
lize out, leaving a mother liquor containing the iodids. Chlorin, 
obtained from bleaching powder, decomposes the iodids and free 
iodin distils over. With potassium iodid the reaction is: 

K-,F + CI = K-,C1' + I. 



IODIN 145 

Properties. — Physical. — Iodin deviates from bromin in the 
same direction that bromin deviates from chlorin: chlorin is a 
gas, bromin a liquid, and iodin a solid. Its crystals are blue- 
black, soft, and scaly, having a metallic luster and an unpleasant 
taste. The specific gravity of iodin is 5; it melts at 114 C. 
(237 ° F.) and boils at 175 ° C. (347 ° F.). At all temperatures 
iodin gives off a vapor possessing a characteristic odor and a 
violet color, to which latter the name of the element is due (iodes, 
violet). If a large flask be strongly heated by constant turning 
over a large flame, and a few crystals of iodin be then thrown in, 
a heavy vapor of a dark violet color forms. The specific gravity 
of this vapor is 8.716. 

The crystals are only sparingly soluble in water, but if an 
excess of iodin be left in the bottle in time a larger amount is 
taken up, some of it passing into the state of hydriodic acid (HI) 
by a decomposition of water similar to that caused by chlorin 
and bromin. This hydriodic acid assists in dissolving the iodin. 
If the water contain an iodid, such as potassium iodid, much 
larger quantities of iodin pass into solution. 

This phenomenon, like a similar one described under Bromin 
(p. 142), is due to the formation of an easily decomposed com- 
pound, in which the colorless iodidion, F, of the salt becomes 
brown tri-iodidion, I/. In using it, as fast as the free iodin is taken 
away, the I 3 ' is broken up to F in the iodid and neutral iodin I 2 , 
which replaces the free iodin in solution. This property is em- 
ployed in the highly iodinized official preparations, all of which 
contain potassium iodid as well as iodin, tinctura iodi, liquor 
iodi compositus, or LugoVs solution; unguentum iodi, or LugoVs 
ointment, and tinctura iodi composita, or Churchill's tincture. 

Iodin is very soluble in alcohol, forming the dark red-brown 
tincture (7 per cent, of iodin). When dissolved in ether it has 
the same red-brown color, but in chloroform, benzene, and carbon 
disulphid its solutions are a fine violet color. As carbon disulphid 
is a heavy colorless liquid not miscible with water, it may be 
used to show the phenomenon of separation by the difference 
of solubility, which is as 1 : 700. The brown solution of iodin 
in water loses its color when shaken with carbon disulphid, the 
disulphid being turned a deep violet and separating as a bottom 
layer. That this applies only to the elementary iodin is shown 
by adding potassium hydroxid to the water and shaking the 
fluids again. The violet color disappears from the carbon disulphid 
as the iodin changes to potassium iodid and passes into its better 
solvent, the water. 

Chemical. — Closely akin to chlorin and bromin in its reactions, 
iodin is less active than either. It has feeble bleaching and 



146 NON-METALS 

oxidizing powers and decomposes water slowly. Ozone forms 
an oxid with it, but oxygen does not. Ammonium hydroxid con- 
verts iodin into an explosive, nitrogen iodid. It is oxidized by 
nitric acid into iodic acid. 

Amylum iodatum, or starch iodid, is a compound having 
a deep-blue color, and is formed when a cold solution of boiled 
starch is treated with free iodin. Although this is a compound, 
yet as the union is not very strong, it has to some degree the 
chemical and medical properties of iodin. This characteristic 
reaction is used to detect both starch and iodin. 1 Should the 
indications be doubtful, the blue fluid may be heated, when the 
blue starch iodid will dissociate and the brown color of free iodin 
appear. When cooled, the blue compound is restored. 

Iodids have a resemblance to the chlorids and bromids, and 
are formed by similar reactions. All the metallic iodids are sol- 
uble, except those of silver, lead, and the mercurous salt. The 
lead iodid is feebly soluble. Chlorin displaces iodin as it does 
bromin. 

Incompatible^. — The alkalies, alkaloids, metallic salts, starch, 
tannin, and turpentine. 

Medical Uses. — Free iodin is a local escharotic, discutient 
and disinfectant. Internally, it is an alterative for scrofulosis. 

Toxicology. — By mistake, though rarely, the tincture and 
the liniment have been taken internally with poisonous effects. 

Symptoms. — It acts as a powerful irritant upon the stomach 
and bowels, causing pain in the mouth, throat, and stomach, 
vomiting and purging, extreme thirst, fainting attacks, and col- 
lapse. When applied by surgeons freely to absorbing surfaces, 
it may cause systemic disturbances, such as headache, dizziness, 
mental trouble, along with the above gastric symptoms brought 
about indirectly. Its elimination by the kidneys involves those 
organs in inflammation, which may end in suppression of urine. 

Fatal Dose. — Death has resulted from 1 fl. dr. of the tincture, 
containing less than 2 gr. of the element. Ten or 20 gr. of the 
solid would probably be fatal. Recovery has followed a dose of 
1 fl. oz. of the tincture. 

Fatal Period. — While death has occurred in twenty-four hours, 
in cases of poisoning from external application it will be delayed 
for several days. 

Treatment. —Large drafts of tepid water will assist in evacu- 
ating the stomach. The antidote is starch in some form, best given 
in decoction, such as the clear starch of the laundry; or as gruels, 

1 A sensitive starch paste is best made by grinding a small amount of laundry- 
starch in a mortar with cold water and then pouring it into hot water at the boiling- 
point while stirring. Heat is withdrawn and after cooling the thin, clear solution 
detects the merest trace of iodin. 



IODIN 147 

boiled rice, or arrow-root, given as long as the vomited matters 
have a blue color. 

Postmortem Appearances. — The morbid changes found are 
such as attend gastro-intestinal irritation, leading to inflammation 
and excoriation. 

Detection. — By agitating organic matters or an aqueous solu- 
tion of iodin with carbon bisulphid the iodin is separated, making 
a violet-colored solution. If the iodin is combined, a very small 
quantity of chlorin-water must be used to liberate it. A decoction 
of starch which has been allowed to cool gives a dark-blue color, 
due to the formation of iodid of starch. The yellow stains on the 
skin and lips are removable by ammonia, which would only deepen 
the stain if due to nitric acid. 

"lodism." — Excessive doses of iodids or the persistent use of 
average doses may induce the symptoms of "iodism." These 
are frontal headache, catarrh, general malaise. The face swells 
and skin eruptions appear. Fatal cases are rare. 

Hydrogen Iodid. — This is a colorless gas having the for- 
mula HI, and, like HC1, dissolves freely in water, forming hydri- 
odic acid. This acid closely resembles the hydracids of chlorin 
and bromin, and can be prepared by passing hydrogen sulphid 
through an aqueous solution of iodin until the latter is decolor- 
ized: 

H 2 S + I 2 2HI + S. 

Hydrogen sulphid. Hydriodic acid. 

If allowed to stand in the air, the colorless acid becomes oxi- 
dized, turns brown, and eventually disappears, while crystals of 
free iodin form. 

4 HI + 2 = 2 H 2 + 2l 2 . 

Syrupus acidi hydriodici (U. S. P.) contains 1 per cent, 
absolute HI. Dose: 30 to 60 TTL (1.90-3.80 c.c). It is prepared 
by the action of an alcoholic solution of tartaric acid upon potas- 
sium iodid. It is supposed to represent the medical powers of 
iodin without causing gastric irritation. 

Oxy acids. — The effect of mixing iodin with caustic soda corre- 
sponds to that of mixing chlorin with the same hydroxid. First, 
the hypoiodite, NalO, is formed; in a short while this changes 
to sodium iodate, NaI0 3 , and sodium iodid, Nal. The acid from 
which the iodate is derived is iodic acid, HIO s . 

Iodic acid is a very stable, white crystalline substance, soluble 
in water and imparting to it the properties of a strong acid. It is 
odorless and has a bitter taste. It is used as a test for morphin, 
as it yields its oxygen readily and is thus reduced to brown ele- 
mentary iodin. 



148 NON-METALS 

Periodic acid, HI0 4 , is formed when sodium iodate is oxidized 
by the action of chlorin. Taking up 1 atom more of oxygen, 
sodium periodate is produced. From this salt the acid can be 
obtained as colorless crystals, soluble in water and decomposable 
by heat. In this form it has 2 molecules of water combined with 
it, giving a formula H 5 IO e . 

FLUORIN 

Symbol, F. Atomic weight, 19.05. 

Occurrence. — In nature fluorin exists in large quantities as 
fluorspar, calcium fluorid, CaF 2 , and in cryolite, a fluorid of alu- 
minium and sodium, Na 3 AlF 6 . Like the other halogens, fluorin 
is not found free in nature, owing to its active affinities for many 
substances. 

Preparation. — When anhydrous hydrogen fluorid is con- 
verted into a conductor by dissolving in it calcium fluorid, the 
hydrogen fluorid is decomposed by the electric current, with 
fluorin separating at the anode. Vessels of platinum or copper 
resist the fluorin fairly well and are used instead of glass. 

Properties. — Fluorin is an almost colorless, faintly yellow 
gas with a specific gravity of 1.265. ^ * s condensed to a liquid 
at — 187 ° C. ( — 304° F.). It combines with every element except 
oxygen and the argon family, and generally with great energy. 
All sorts of hydrogen compounds yield their hydrogen to it, with 
the evolution of light and heat. 

Hydrogen Fluorid (HF).— This gas is prepared by gently 
heating in a lead dish a mixture of calcium fluorid and sulphuric 
acid. If it be covered with a glass plate the glass is corroded 
wherever it is exposed. By previously coating the glass with 
wax or paraffin and scratching with a needle through the wax the 
glass may be etched in ruled lines or ornamental figures. In 
this experiment aqueous vapor mixes with the gas. When abso- 
lutely dry the gas does not act on glass. The reaction is as follows: 

CaF 2 + H 2 S0 4 = 2HF + CaS0 4 

Calcium fluorid. Calcium sulphate. 

Hydrofluoric Acid. — The gas dissolved in water becomes a 
fuming liquid, which can not be kept in glass. Gutta-percha bot- 
tles, however, resist the action of the acid and are used as con- 
tainers. The reaction with glass is shown in the following equa- 
tion to be a conversion of the silicic acid into a gas, silicon fluorid: 

Si0 2 + 4 HF = 2 H 2 + SiF 4 

Silicic acid. Hydrofluoric acid. Silicon fluorid. 

Toxicology. — Like hydrogen chlorid, this gas is highly irri- 
tating when inhaled, and the liquid acid corrodes the parts with 



THE CHLORIN FAMILY 



149 



-which it comes in contact. The antidote, when inhaled, is 
ammonia vapor; or, on the burned surfaces, weak alkalies to 
neutralize the acid. 

Sodium fluorid is sometimes added to beer as a preservative. 
The amount in a single bottle has no noticeable effect, but if the 
preserved beer is taken habitually as a beverage the effects accumu- 
late. They are seen in the neuralgias, weak heart, dropsies, 
phlebitis, painful urination, and loss of calcium salts from the 
system, impairing nutrition of the bones. 

THE CHLORIN FAMILY OR HALOGENS 

In a former section a list of the elements w T as given (see p. 117), 
arranged, according to a natural system, by their numeric pro- 
gression in valence and atomic weights. This system was based 
upon the observation that in many cases elements that resemble 
one another could be grouped in triplets, the middle member of 
which was not only intermediate in properties, but also had an 
atomic weight very nearly the mean of two extremes. Thus, in 
the order of atomic weights, 01 = 35.5, Br = 8o, 1=127, the mean 
is 81.25. 

35-5 + 127 = 81.25. 



Other examples are P = 3i, As=75, Sb=i20, the mean 75.5. 
The calcium group: Ca = 4o, Sr = 87.5, Ba=i37, the mean is 
88.5. 

The similarities of the chlorin group with the gradation in 
properties according to the atomic weights are shown in the fol- 
lowing summary: They are all univalent, all volatile, and all 
form colored gases that are pungent and irritating. At room 
temperature CI is a gas, Br is a liquid, I a solid. Their boiling- 
points rise in the same order with their specific gravities. In 
their chemical conduct and their bleaching and disinfectant powers 
CI has the strongest affinities, Br next, and I last; thus illustrating 
a general principle, that in such a group the energy is inversely 
as the atomic weight. The lighter halogen always displaces the 
heavier from its salts, i. e., the lighter forms ions; the heavier, 
elementary molecules. The tendency to ion formation is great 
in fluorin but very slight in iodin. The activity and stability of 
their hydrogen acids follow the same law, but the order for the 
oxygen acids is reversed. As for solubility in water, CI is readily 
soluble, Br moderately, I feebly. Their salts with metals (called 
haloid) crystallize in cubes and are among the best germicides 
known. These elements are called halogens (hals, sea-salt) 
because they are generated from the sea: CI from sea-water, Br 



150 NON-METALS 

from sea-salt, I from seaweed. Fluorin is classed with the halo- 
gens, though there is a wider step from it to chlorin than there is 
between the other members of the series. It resembles the mem- 
bers of this group, however, more than it does those of any other. 
Facts like those just stated might be adduced from other 
groups, all going to justify the empiric law formulated by Men- 
delejeff, that the properties of the elements are a periodic junction 
of their atomic weights (p. 116). These relationships are recog- 
nized as pointing to the conclusion that in the closely allied ele- 
ments of a group there is a common constituent. A more sweeping 
generalization is that all the elements are species or variations of 
one primal stuff. They are unmistakably akin, hence they 
probably have one common ancestry. 

SULPHUR (Brimstone) 

Symbol, S. Atomic weight, 32.06. 

Occurrence. — In volcanic regions, especially those of Sicily, 
this element is found free and almost pure. In considerable 
amounts it is found in its natural compounds, the blendes, glances, 
pyrites, and galena, in the hydrogen sulphid of sulphur waters, 
and the albumin of animals. 

Preparation. — Native sulphur is melted by setting fire to it, 
and while liquid it is run off from the unfused minerals associated 
with it into cylindric molds. In this form it is called crude brim- 
stone. It is refined by distillation or sublimation and condensation. 
The vapor, received into a cool chamber, is deposited, first, as small 
crystals, making the yellow powder known as jlowers of sulphur. 
As the chamber warms, the sulphur condenses into a liquid at the 
bottom and is drawn off into molds to make roll sulphur. 

Physical Properties.— The native element is found as elon- 
gated octahedral crystals of a honey-yellow color, with a very 
faint taste and odor. Pure sulphur may fail to answer to the odor 
test, but if a small piece be laid on polished silver it gives off suffi- 
cient vapor in a few days to make a brown halo of silver sulphid. 
The effect on the silver accumulates by time until it is perceptible, 
while that on the sense of smell is necessarily transient, and not 
intensified by time. It is insoluble in water, but soluble in hot 
alcohol, chloroform, ether, carbon bisulphid, oils, and alkaline 
solutions. It melts at 114 C. (237.2 ° F.) to a thin straw-colored 
liquid, which becomes thick and brown, like molasses, as the 
heat rises to 160 C. (320 F.); at 250 C. (482 ° F.) it becomes 
dark red and viscid; gets thin and yellowish again at 340 ° C. 
(642 ° F.), until it reaches 440 C. (824 F.), when it boils, emit- 
ting a brownish vapor. These phenomena are remarkable excep- 



SULPHUR 151 

tions to the rule that fluids become more mobile as the internal 
friction is lessened by the rise of temperature. On cooling, the 
hot sulphur passes through the same stages in the reverse order, 
solidifying as prismatic crystals. 

Heat has a peculiar effect in changing the vapor density of 
this element, and, as the molecular weight is twice the vapor 
density, we can calculate the changes as variations in the mass of 
the molecule. These variations are due apparently to varying 
mixtures of two allotropic forms of the element in the state of 
vapor, in one of which there are two atoms to the molecule S 2 and 
the other sight atoms S 8 . The 8-atom molecule, S 8 , at 440 ° C. 
(824 F.) dissociates at 1000 C. (1832 ° F.) into 4 diatomic 
molecules 4(S 2 ). 

Amorphous Sulphur. — If the dark brown melted sulphur 
at or above 250 C. (482 ° F.) be suddenly cooled by pouring 
it into cold water, it becomes a soft tenacious mass similar to 
elastic rubber. This condition is not permanent, for in some 
hours it changes into an opaque brittle mass of rhombic octahedra. 
If crystallization occurs at temperatures above 100 ° C. (212 ° F.), 
the sulphur forms oblique prisms, in no way resembling the octa- 
hedra. Sulphur exists then in two crystalline, and one amorphous, 
varieties. 

Prismatic or Monoclinic Sulphur. — This is formed after fusion 
and is an amber yellow, having a specific gravity of 1.95, and 
melting at 120 C. (248 F.). 

Rhombic octahedral sulphur is found in nature and results 
when sulphur is deposited from solution in carbon bisulphid. It 
has a specific gravity of 2.05 and melts at 114.5 C. (238 ° F.). On 
exposure to the air for several days each monoclinic prism ceases 
to be transparent and splits into octahedra. 

Official Preparations. — Sulphur sublimatum, or flowers of 
sulphur, deposited from subliming the crude element, is an impure 
preparation used externally in medicine. Sulphur lotum is sulphur 
washed in water to free it of some of the sulphuric acid generated 
during sublimation. Sulphur prcecipitatum, lac sulphuris, milk 
of sulphur, is a white powder so finely divided that the yellow color 
is lost. It is prepared by dissolving sulphur in water by means 
of lime, and precipitating with hydrochloric acid. It is the most 
active form for medicinal use. Dose: J to 2 dr. Unguentum 
sulphuris is a 15 per cent, ointment used as a parasiticide in skin 
diseases. 

Chemical Properties. — Sulphur, when heated, takes fire, burn- 
ing with a pale-blue flame and forming sulphur dioxid. As a com- 
ponent of gunpowder it generates the same gas. Sulphur burns 
in hydrogen sulphid. Like oxygen, it is at times divalent and can 



J 52 



NON-METALS 



replace that element to generate compounds resembling those 
of oxygen. To indicate this the prefix thio- is used before the 
name of the oxygen compound. Thus, HOCN is cyanic acid 
and HSCN is thiocyanic acid. 

Crystallography. — A solution of sodium chlorid, like that 
of most solids, when evaporated to a thick fluid and set aside, 
crystallizes — that is, the molecules of the solid separate in reg- 
ular geometric form. The same phenomenon is observed when 
vapors of iodin, arsenic trioxid or other substances solidify. A 
body is called a crystal when it has many sides or plane surfaces, 
more or less symmetric, intersecting at definite angles. That 
there is an internal structure is shown by a tendency to break with 
planes of cleavage corresponding to the external surface planes. 
A well-known example is mica. Crystals transmit heat, light, and 
electricity differently in different directions, owing to this peculiar 
arrangement of their deep-seated parts. Perfect crystals, are rare, 
because the conditions are seldom ideal. Before the shape is 
symmetrically developed another crystal may separate which is 
superimposed and, therefore, impedes the growth of the first 
formed. Still, as the angles are well defined and the relationship 
of the faces preserved, these constants are sufficient data for 
geometry to construct the ideal form of the crystal. There are 
substances, like gum, resin, and glass, which never show geometric 
structure, and are, therefore, called amorphous, or formless. These 
do not break in planes of cleavage, but conduct heat and electricity 
and transmit light equally well in all directions. 

The crystalline form is a very definite property which forces 
itself upon our observation and is as characteristic as the points 
of freezing and boiling. It is a valuable means of identification, 
and is, therefore, classed among the significant characters of a 
substance. 

The manifold external shapes of crystals can all be referred to 
one of six systems characterized by their imaginary axes and planes 
of symmetry. 

i. The regular system includes crystals with three equal imag- 
inary axes crossing in the center at right angles to each other. 
The simplest form is the cube (Fig. 42) with the axes terminating 
in the center of the surfaces. (Examples: sodium chlorid and 
other haloid salts.) If the solid angles of the cube be cut off, the 
law of its symmetry is preserved and a secondary form appears, the 
right octahedron (Fig. 45). (Examples: diamond, alum, arsenic 
trioxid.) By cutting off the edges of the octahedron and cube 
symmetrically the third derivative is obtained, the rhombic dodeca- 
hedron (Fig. 43). (Example: garnet.) The regular tetrahedron 
(Fig. 44) is obtained by cutting off the alternate solid angles of the 



CRYSTALLOGRAPHY 



J 53 



cube or extending the alternate faces of the octahedron (Fig. 44). 
(Example: boracite.) 






f^^M 


/C"^ /'/ 


\V \ 


/ /V . 


' \\ \ 


/ /' 'V \ 




/'----/K; 


x\~— ~\ 




■""^c^M 


1 / X 

/ / \ \ 
If \ l 


/'' \ \ 




/' ^M 



Fig. 42. — Cube. 



Fig. 43. — Dodecahedron. 



Fig. 44. — Tetrahedron developed 
from octahedron. 



2. The quadratic system includes crystals with three axes inter- 
secting at right angles, two of which are of equal length, the 
third differing and being called the prin- 
cipal axis. The simple forms are the 
right square-based octahedron (Fig. 45) 
and the right-square prism with a termi- 
nal plane at right angles to the principal 






Fig. 45. — Quadratic octahedron. 



Fig. 46. — Quadratic prism 
with pyramidal end. 



axis, or with terminal pyramids (Fig. 46). (Example: potas- 
sium ferrocyanid.) 




Fig. 47. — Double six-sided 
pyramid.! 



Fig 





Fig. 49. — Rhombohedron. 



3. The hexagonal system contains the forms referred to four 
axes, three of equal length, inclined to 6o° to each other, and the 
fourth, of any length, at right angles to the other three. The 
fundamental form is the double six-sided pyramid (Fig. 47). 



*54 



NON-METALS 



Another form is the hexagonal prism which, combined with the 
pyramids, gives the shape of the quartz crystal (Fig. 48). By 
developing the alternate faces of the double pyramid the rhombo- 
hedron is formed (Fig. 49), as in calcite or Iceland spar. (Exam- 
ple: ice.) 

4. The orthorhombic system includes crystals that have three 
axes of unequal length intersecting at right angles to each other. 
The principal forms are the right octahedron or double four-sided 
pyramid with rhombic base (Fig. 51) and the right rhombic prism. 
(Examples: native sulphur and niter.) 

5. The monoclinic and oblique system contains the crystals 
that can be referred to three axes, of equal or unequal length, two 
of them at acute angles, and the third at right angles to the other two. 
The fundamental form is a double pyramid with an inclined axis 
and a rhombic base (Fig. 50). Examples: sulphur from fusion, 
ferrous sulphate, sodium carbonate, cane-sugar.) 






Fig. 50. — Monoclinic 
octahedron. 



Fig. 51. — Orthorhombic 
octahedron. 



Fig. 52. — Triclinic 
octahedron. 



6. The triclinic system groups together the crystals which can 
be referred to three axes, all inclined to one another at angles, 
not right angles. These crystals are the least symmetric, for 
only the parallel and opposite faces are equal, as in the doubly 
oblique octahedron (Fig. 52). (Examples: potassium bichromate, 
copper sulphate.) 

When a substance has two definite forms, like sulphur, it is 
said to be dimorphous . These forms are found to differ in their 
specific gravities and other properties. Very rarely instances 
occur of the same substance forming crystals referable to three 
different systems; such substances are said to be trimorphous. 
There are many substances of different composition which crys- 
tallize in the same forms, and hence are said to be isomorphous. 
Among these there often exists a certain correspondence in the 
constitution of the molecules, as in the class of salts of different 
metals known as alums, so-called from their resemblance to the 
type, common alum. 

Hydrogen Sulphid (H 2 S) (Sulphydric Acid, Sulphur eted 



SULPHUR 



*55 



Hydrogen). — Occurrence. — Mineral springs of the class known as 
sulphur waters contain this gas. It is a product of the putre- 
factive fermentation of proteid substances, and hence is found in 
foul abscesses and in small amounts in the flatus of the intestines. 

Preparation. — The most convenient method of preparation, 
and the one generally used, is that consisting in the action of 
dilute sulphuric acid on ferrous sulphid. Hydrochloric acid and 
antimony sulphid may also be used. In coarse pieces the ferrous 
sulphid is put into the usual hydrogen-generating flask (Fig. 28) 
and sulphuric or hydrochloric acid in the proportion of 1 : 6 of water 
is added as required. A wash-bottle containing water is attached 
to remove impurities. Kipp's apparatus (Fig. 53) is a convenient 




Fig. 53. — Kipp's apparatus for hydrogen sulphid, with wash-botdes attached. 

source of the gas in a regulated supply. It has three vessels 
superposed; in a is the dilute sulphuric acid which is fed from c. 
It rises until it acts on the ferrous sulphid in the generator b; the 
gas confined presses out the acid, which then rises to c, and action 
ceases until the gas is allowed to escape at the cock, when the 
acid descends to its first position. The gas is washed in d, and 
acts on the metallic solution in e. 



FeS 


+ 


H 2 S0 4 


FeS0 4 


+ 


H 2 S 


Ferrous sulphid. 




Sulphuric acid. 


Ferrous sulphate. 




Hydrogen sulphid 


FeS 


+ 


2HC1 


FeCl 2 

Ferrous chlorid. 


+ 


H 2 S. 



Physical Properties. — Hydrogen sulphid is a gas without color, 
but having the disgusting odor and taste of rotten eggs. It is 



156 NON-METALS 

slightly heavier than the air; specific gravity 1.19. At — 74 ° C. 
(—101. 2 F.) it liquefies, and at — 85.5 ° C. (—122° F.) it freezes 
into white crystals. One volume of water absorbs three of this 
gas to form a colorless solution having the odor and chemical 
powers of the gas itself. On boiling, all the gas is expelled. While 
this solution is useful in the laboratory, it is not stable, soon taking 
oxygen from the air to form water with the deposit of sulphur. To 
prevent this deterioration the water should first be boiled to expel 
the dissolved oxygen, and the solution then kept in well-filled and 
well-stoppered bottles. This solution is sometimes called sul- 
phydric acid. With ammonia it forms two compounds, ammonium 
sulphid, (NH 4 ) 2 S, and ammonium sulphydrate, (NH 4 )HS. 

Chemical Properties. — If delivered at a jet, hydrogen sulphid 
burns with a blue flame, forming sulphur dioxid and water: 

H 2 S + 3O = S0 2 + H 2 0. 

An explosive mixture results when air is added to hydrogen, 
sulphid. Soluble sulphydrates or hydrosulphids are produced by 
passing it into a solution of an alkaline hydroxid: 



KHO + H 2 S = H 2 + KHS. 

Potassium hydroxid. Potassium hydrosulphid,. 

As a Group Reagent. — Solutions of the heavy metals (p. 210),. 
when charged with hydrogen sulphid yield sulphids and the acid 
of the salt is set free: 



CuS0 4 


+ 


H 2 S 


CuS 


+ 


H 2 S0 4 . 


Copper sulphate. 






Copper sulphid. 




Sulphuric acid. 



The copper sulphid is thrown down as a brownish-black pre- 
cipitate. With zinc sulphate a scanty white precipitate of zinc 
sulphid is produced according to the equation: 

ZnS0 4 + H 2 S = ZnS + H 2 S0 4 . 

Even with excess of H 2 S all the zinc is not precipitated, but some 
of its sulphid remains in solution. The addition of potassium 
hydroxid by removing the free H 2 S0 4 , causes a further precipitate 
of ZnS. If this ZnS be collected on a filter and treated in a test- 
tube with sulphuric acid, H 2 S is liberated by a reaction, the reverse 
of that given above. This reversible character is shown in the, 
equation 

ZnS + H 2 S0 4 ^ ZnS0 4 + H 2 S. 



SULPHUR 



J 57 



The movement may be in either direction according to which 
side is in the ascendant by its concentration. Much H 2 S + ZnS0 4 in 
the solution causes the formation of ZnS + H 2 S0 4 , whereas a large 
amount of H 2 S0 4 carries the action toward the formation of ZnS0 4 
+ H 2 S. This is a notable illustration of the effect of mass and of 
the rule that the operation of every reaction is limited according 
to the products present. 

The different metallic sulphids behave differently to weak acids : 
When insoluble in acids (as is the case with sulphids of Pb, Bi, Ag, 
Hg, Cu, Cd, As, Sb, Au, Pt, Sn) there is a precipitate with hydrogen 
sulphid; when soluble in the acids (as is the case with sulphids of Fe, 
Co, Ni, Mn, Zn, Th, Ur) an alkali solution with the hydrogen sul- 
phid precipitates them. This latter class is more conveniently 
precipitated by adding an alkaline sulphid or ammonium sulphid: 



ZnCLj 


+ 


(NH 4 ) 2 S 


ZnS 


+ 


2 NH 4 C1 


Zinc chlorid. 




Ammonium sulphid. 


Zinc sulphid. 




Ammonium chlorid. 



The metals of the alkalies and alkaline earths form with hydro- 
gen sulphid soluble sulphids and make the analytic group of metals 
not precipitated by hydrogen sulphid or by ammonium sulphid. 

Toxicology. — If inhaled pure, this gas is immediately fatal, and 
even when diluted to i per cent, it kills, though more slowly. 
As a constituent of the gas of privies, burial vaults, sewers, and 
the slag heaps of chemical works its minor toxic symptoms are 
often seen. They are nausea, vomiting, depression, giddiness, 
headache, labored breathing, stupor, and coma. In laboratories 
it should not be used outside the fume chamber. The air con- 
taminated with it acts as an insidious poison, partly by its power 
of reducing the hemoglobin of the blood-corpuscles, but mainly 
as a direct paralyzer of the nerve centers of the lungs and heart. 

Postmortem Appearances. — The blood is liquid and dark brown 
in color, from the sulphid of iron formed with the red coloring- 
matter. A silver coin inserted into an incision blackens, even 
before putrefaction sets in. 

Treatment consists in prompt removal to pure air, artificial 
respiration, inhalations of oxygen, warmth to the extremities, and 
stimulants. 

Detection. — The odor is perceptible when i part is present in 
10,000 of air. This may be confirmed by exposing a piece of 
white filter-paper soaked in solution of lead acetate; it blackens. 

Sulphur Dioxid (S0 2 ) {Sulphurous Anhydrid).— Preparation. 
— When sulphur is burned in oxygen or in the air, direct union 
occurs: S + 2 = S0 2 . This method for the generation of sul- 
phur dioxid is used for the disinfection of rooms. Sulphur dioxid 
is formed when certain sulphids, like pyrites, FeS 2 , are roasted in 



158 NON-METALS 

the air, as in the first step in the manufacture of sulphuric acid. 
One method of extemporaneous generation without heat con- 
venient for the laboratory is to have on hand a solution of sodium 
bisulphite made from that salt or prepared by charging a solution 
of sodium carbonate with sulphur dioxid. This solution is 
placed in a tap-funnel of the apparatus Fig. 37. In the flask is 
concentrated sulphuric acid. On opening the cock, the bisulphite 
solution drops into the acid and S0 2 is set free at any desired rate. 

NaHSO, + H 2 S0 4 = NaHS0 4 + H 2 + S0 2 . 

Sodium bisulphite. Sodium bisulphate. 

The usual laboratory method is by heating strong sulphuric 
acid with copper in a flask seen in Fig. 41: 2H 2 S0 4 + Cu = CuS0 4 
+ 2H 2 + S0 2 . Owing to its solubility in water the pneumatic 
trough is not used, but the gas is collected in upright jars with 
glass stoppers greased with vaselin. 

Physical Properties. — Sulphur dioxid is a colorless gas with a 
stifling odor and a persistent taste, familiar in the odor and taste 
of the smoke of sulphur matches. Its specific gravity is 2.23; 
hence, it may be collected by downward displacement. At room 
temperature it is readily liquefied under three atmospheres of 
pressure, or under ordinary pressure if cooled artificially by a 
mixture of ice and salt to — io° C. (14 F.). It freezes at — 75 ° 
C. (—103° F.). Compressed in siphons, sealed cans, or steel 
cylinders it is a market product. 

Chemical Properties. — Sulphur dioxid does not burn nor will 
it support combustion. If a handful of flowers of sulphur be 
thrown down a burning chimney the fire will be extinguished. 
The sulphur takes fire and yields S0 2 , which smothers the flames. 
When S0 2 is passed into solutions of metallic hydroxids it forms 
sulphites or bisulphites, according to the amount of hydrogen 
replaced. 

Acidum Sulphurosum. — Water dissolves about 50 times its vol- 
ume of the gas at ordinary temperatures, resulting in the official 
sulphurous acid, H 2 SO s (Fig. 41). After a bottle is filled with 
the gas a little water is added, the bottle closed and shaken; on 
opening again the air rushes in to take the place of the gas absorbed 
by the water. A test-tube filled with dry S0 2 and inverted with 
the mouth under water slowly fills with water. It is a colorless 
liquid with an acid reaction first reddening litmus and afterward 
bleaching it, and forms two classes of salts represented by sodium 
sulphite, Na 2 S0 3 , in which sulphosion (S0 3 )" is divalent, and 
sodium bisulphite, NaHSO s , containing univalent hydrosulphosion 
(HS0 3 )'. It is a weak acid, decomposing by heat into H 2 0-|- 
S0 2 . Sunlight causes rapid deterioration by oxidation. 



SULPHUR 159 

The moist gas and even more, the acid solution, are characterized 
by their readiness to take one more atom of oxygen from sub- 
stances rich in that element. They are, therefore, called powerful 
reducing agents, being converted themselves into a higher oxygen 
compound, sulphuric acid: 

S0 2 + H 2 + O H 2 S0 4 . 

A striking exhibition of this reducing property is seen when 
the purple solution of potassium permanganate is added to sul- 
phurous acid. The color is discharged, due to the yielding of 
oxygen to the H 2 S0 3 , which becomes H 2 S0 4 . Sulphur dioxid is 
also a bleaching agent, taking oxygen from vegetable dyes. This 
may be shown by burning sulphur near moist flowers under a 
bell jar. The flowers lose their color, which, however, can be 
partly restored by immersion in weak sulphuric acid. 

With powerful reducing agents the gas may give up its oxygen, 
thus becoming an oxidizing agent: 

4 S0 2 + 3 H 2 S = 2 H 2 + H 2 S 5 6 + S 2 . 

Hydrogen sulphid. Pentathionic acid. 

Medical Uses. — Sulphur dioxid is very destructive to plant 
life, high and low. A few pounds of sulphur burned in a mouldy 
cellar or conservatory causes the minute fungi to disappear. 
This property makes it valuable as an aerial disinfectant and 
vermin-killer. For every 1000 cu. ft. 4 pounds of sulphur must 
be burned. The sulphur candle may be used, or a mixture of 
flowers of sulphur and turpentine may be fired, if supported 
by bricks in a washtub containing water. As the gas is irre- 
spirable, the combustion cannot be watched. The room must 
be kept tightly closed for twenty-four hours, and then aired 
before being occupied. All bugs, fleas, mosquitoes, and many 
bacteria are destroyed by this means. Many fabrics left in such 
an atmosphere are bleached, and perishable foods, such as meats 
and fruit, are made preservable for days. This preservative 
property is shared by its salts, the sulphites and bisulphites, which 
are often dusted over meats to prevent decay. Digestion of 
foods so preserved is retarded because the antiferments interfere 
with the activity of the enzymes of digestion. Sulphurous acid and 
the sulphites are prohibited by U. S. law (1908) as preservatives 
of food. Sulphur dioxid is not condemned when used in fumi- 
gating wines, dried fruits, or sugars to the extent of 350 mg. per 
kilogram left in the product. In these cases a certain amount 
combines with aldejiyd and sugar to make harmless compounds, 
but any excess is toxic. Acidum sulphur osum is a parasiticide 



l6o NON-METALS 

for skin diseases. It is given internally to check gastric fermenta- 
tions. Dose: f^ss-j (2-4 c.c), largely diluted. 

Tests. — The stifling odor of burning sulphur matches is char- 
acteristic of sulphur dioxid. Starch-paper moistened with a solu- 
tion of iodic acid turns blue when exposed to air containing 1 part 
of S0 2 in 3000. 

Sulphur Trioxid (S0 3 ) {Sulphuric Anhydrid). — Preparation. 
— In burning sulphur most of it becomes S0 2 , but a small quan- 
tity of misty substance is formed which has the formula SO s . 
When fuming sulphuric acid is heated it decomposes with the 
production of S0 3 . 

H 2 S 2 7 = H 2 S0 4 + S0 3 . 

Pyrosulphuric acid. Sulphuric acid. Sulphur trioxid. 

Properties. — Sulphur trioxid is a transparent colorless liquid 
which freezes at 16 ° C. (60.8 ° F.) to a white solid. After being 
kept awhije a modified form is produced at ordinary temperature, 
forming white asbestos-like crystals. This white solid dissolves 
in water with a crackling sound, resulting in H 2 S0 4 and evolving 
much heat. It is used by dyers as an oxidizing agent. 

Sulphuric Acid (H 2 S0 4 ) (Oil oj Vitriol). — Occurrence.— In 
almost every technical process this acid is used at one stage or 
another. Its manufacture is of supreme importance in the arts, 
and illustrates some most interesting reactions. 

Preparation. — Under the demand for sulphur trioxid in the 
manufacture of artificial indigo the catalytic method has been 
brought to a point of practical efficiency and economy. The 
theory is simplicity itself: By heating in the air ores of sulphur 
and iron (pyrites) S0 2 is formed. This is purified, cooled, and 
with the oxygen of the air passed through cylinders containing 
heated plates holding a mixture of finely divided platinum and 
asbestos. The S0 2 unites directly with O to form SO s , which is 
dissolved in some weak sulphuric acid. It can be obtained of any 
desired strength from the ordinary sulphuric acid to the fuming 
article. Any arsenic in the S0 2 soon stops the action of the 
platinum; hence it is removed before the gas enters the cylinder. 
This insures a product which is arsenic free. As the platinum 
does not enter into the reaction, a small amount serves to oxidize very 
large quantities of the S0 2 . It appears that a union which goes 
on very slowly between S0 2 and oxygen at all times is hastened 
to a high degree by catalysis, due to platinum, which facilitates the 
motion much as a lubricant does in machinery. 

Lead-chamber Process. — This process can be illustrated simply 
by immersing in a vessel containing S0 2 a sliver of wood wet 
with nitric acid. Red fumes of N 2 4 arise, which change to color- 



SULPHURIC ACID l6l 

less N 2 2 when the vessel is closed. Again opening the vessel, 
air enters and N 2 2 forms red fumes of N 2 4 . Eventually crystals 
of nitryl-sulphuric acid appear inside the glass and these are 
washed down with water to form impure H 2 S0 4 . The H 2 S0 4 
can be identified by evaporating with powdered sugar in a por- 
celain dish over a water-bath. The residue turns brown and then 
black. Until recently this was the most accepted method of 
manufacture. It is based on the principle of burning S to S0 2 , 
mixing the gas with H 2 and O of the air, and accelerating their 
union by the aid of nitric acid and nitrogen oxid. Thus: 



(i) 2HN03 


+ 


so 2 


= 


H 2 S0 4 


+ 


N 2 4 . 


(2) 2S0 2 


+ 


N 2 4 


= 


2SO3 


+ 


N 2 2 . 


(3) S0 3 


+ 


H 2 


= 


H 2 S0 4 . 






(4) N 2 2 


+ 


o 2 


= 


N 2 4 . 







These equations show how the nitrogen oxids act as go-betweens, 
taking up oxygen from the air and turning it over to the sulphur 
dioxid. The sulphur trioxid then joins with water to make 
sulphuric acid. The gases are mixed in a series of lead-lined 
chambers. 

The lead lining resists the action of sulphuric acid until it gets 
to 80 per cent. acid. When further concentration is desired, 
this acid is evaporated in flat platinum stills. 

Impurities of the crude acid are due, first, to the arsenic com- 
pounds volatilized from the roasting ore; second, to the lead 
sulphate formed in the chambers; third, to the nitro compounds 
still retained; fourth, to particles of straw and organic dust which 
give it a brownish color. The acid is purified by distillation. 

Properties. — Pure, strong sulphuric acid (acidum sidphuricum, 
U. S.) of a specific gravity not below 1.826 contains not less than 
92.5 per cent, of real acid (H 2 S0 4 ), and is a colorless, heavy, oily 
liquid, not fuming, odorless, extremely sour, combining actively 
with water, and blackening or charring organic substances. It 
crystallizes at 10. 5 C. (50.9 ° F.), and boils at 338 C. (640. 4 F.). 
The commercial oil of vitriol is colored light brown by suspended 
carbonaceous matter and contains small amounts of dissolved 
metals, principally lead and arsenic. When added to water, heat 
is given out. If the proportion of the mixture be 3 of acid to 1 of 
water, the temperature will rise above 100 ° C. (212 F.). It 
has the property of abstracting water from the air, 100 gr. under 
favorable conditions absorbing 120 gr. of water in four days; 
hence its use in desiccators for drying precipitates on filter papers. 
One of the best methods of drying gases is by passing them through 



162 NON-METALS 

concentrated sulphuric acid. This great affinity for water explains 
the charring action upon organic matter such as cane-sugar, paper, 
etc., from which it abstracts the elements of water while dissolving 
all but the black carbon. When the concentrated acid is heated 
with zinc, copper, or other metals, the gas sulphur dioxid is lib- 
erated; if the acid be dilute, then, if any action occurs, the gas 
evolved is hydrogen. 

Nordhausen acid is a form manufactured in Bohemia and used 
largely in chemical industries. It is a dark-brown, heavy, oily, 
fuming liquid, with a specific gravity of 1.9. Its formula is 
H 2 S 2 7 , and it is regarded by some as a solution of SO s in H 2 S0 4 . 
Two weaker forms are used in medicine, the dilute {acidum sul- 
phuricum dilutum, U. S.), of 10 per cent. H 2 S0 4 , and the aromatic 
(acidum sulphuricum aromaticum, U. S.), of 20 per cent. H 2 S0 4 . 
Dose, 10 to 20 Vf[ (0.66-1.23 ex.). 

Medical Uses. — The concentrated acid is applied externally as 
a powerful caustic in the shape of Ricord's paste, made with 
powdered charcoal, and Michel's paste, made with powdered 
asbestos. 

The dilute forms only are used internally as solvents for quinin 
and as a remedy for night-sweats. 

Its incompatibles are the alkalies; alcohol; salts of barium, 
calcium, strontium, lead, mercury, and silver; sulphids. 

Monobasic and Dibasic Acids. — The halogen acids have but 
one combining weight or atom of hydrogen, as HC1, but the three 
sulphur acids already referred to, H 2 S, H 2 S0 3 , and H 2 S0 4 , have two, 
both of which are replaceable by metals. With a bivalent metal, 
like calcium, but one salt is formed, by H 2 S0 4 ; i. e., CaS0 4 , the 
calcium replacing both hydrogen atoms. As one or both of these 
hydrogen atoms may be replaced by a univalent metal, two different 
salts are conceivable. For example, with sodium there are two 
possible reactions: 

H 2 S0 4 + NaHO = NaHSO, + H 2 0; 
and 

H 2 S0 4 + 2 NaHO = Na 2 S0 4 + 2H 2 0. 

Acids, like hydrochloric, which have but one replaceable 
hydrogen atom and which, therefore, react with only one com- 
bining weight of a base to form but one salt, as NaCl, are called 
monobasic. 

Acids, like sulphurous and sulphuric, which react either with one 
or with two combining weights of a base, are called dibasic. They 
have, as a rule, but two atoms of replaceable hydrogen, and when 
these are both replaced by a metal the salt is called neutral or 
normal. Salts of dibasic acids which have one atom of metal 



SULPHURIC ACID 1 63 

retaining one of hydrogen, which is the characteristic component 
of acids, are called acid salts. Sometimes the two salts are desig- 
nated by the prefixes mono- and di- to the name of the metal, as 
NaHS0 4 , monosodium sulphate; Na 2 S0 4 , disodium sulphate. 
Again, they are called primary and secondary. Sometimes they 
are distinguished by calling the normal salt Na 2 S0 4 , sodium 
sulphate; and the acid salt NaHS0 4 , bisnlphate. 

Dissociation of a Dibasic Acid. — Sulphuric acid forms two 
kinds of anions: (1) In concentrated solution the univalent 
hydrosulphanion (HS0 4 )' predominates: H 2 S0 4 = H , ,(HS0 4 )'; 
(2) when diluted this breaks down and dissociates into 2H* and 
the bivalent sulphanion (S0 4 )". When the dilution is sufficient 
there is complete dissociation: H s S0 4 = H*,H",(S0 4 )". If an acid is 
weak, like carbonic acid, H 2 CO b , stage (1) prevails through all 
dilutions, the second hydrogen ion dissociating to only a slight 
degree. The solution of its acid salt, MHA (where M is any 
univalent metal and A a dibasic acid), forms the ions M* and 
(HA) 7 , the group (HA/ scarcely breaking up at all. As there is 
little or no hydrion, there is a very slight acid reaction, and the 
so-called acid salt behaves like a neutral salt; it may even be 
alkaline in reaction, as is sodium bicarbonate, NaHCO s . When 
the acid is strong, like sulphuric acid, dissociation is probably 
complete into H',H # and A /r . On dissolving its acid salt MHA 
the (HAy at first formed undergoes further dissociation into the 
ions H* and A", and the solution finally contains the three ions, 
H*, in relatively large amount, M*, and A". The abundant 
hydrion gives it the properties of an acid. 

Toxicology. — As there are few processes in the arts that do not 
use at some stage the oil of vitriol it can be had at any chemist's. 
It is used for cleansing metals as a household article. In countries 
where the law makes it difficult to purchase the arsenic or alka- 
loidal poisons the ease with which sulphuric acid can be procured 
makes it a very common poison in use by the poorer classes for 
suicidal purposes. It is rarely given in food for homicidal pur- 
poses, because it betrays the poisoner by the altered appearance 
of the charred food, by the stains on the clothing, lips, and tongue, 
by the fiery taste, and by the characteristic symptoms. It has 
been given to young children and even to adults in the form of 
medicine, taken, as disagreeable doses usually are, from a spoon 
back of the tongue, so as to avoid tasting. 

Poisoning has occurred from the accidental substitution of 
sulphuric acid for oils, syrup, or glycerin. It has been poured 
into the ear, given by enema, and even injected into the vagina. 

Local External Effects. — Malicious persons resort to sulphuric 
acid to disfigure the face or ruin the clothes by throwing a quantity 



164 NON-METALS 

of it at the hated person. Occasionally in chemical laboratories, 
while experimenting with it, flasks containing it will burst and the 
contents be dashed into the face of the experimenter. If it strike 
the eye, blindness may result. In contact with the skin it causes 
great agony and a lasting scar. Instant action is necessary to 
prevent these serious effects. Water must be applied freely, the 
whole face immersed in a basin of it or held under a running tap, 
and the eyes opened under the water. A paste of sodium bicar- 
bonate or a piece of soap will help to neutralize the residual acid 
at the burned points. The burn may be treated afterward with 
linimentum calcis. It is a common accident in the laboratory for 
the acid to fall upon the clothing. If not promptly touched with 
ammonia or some alkaline solution, the spot turns red and soon 
becomes rotten. 

Symptoms. — On the instant of contact with the mouth there is 
intense pain, extending down the throat and gullet to the pit of 
the stomach, along the track of the acid. The tongue swells until 
it fills the mouth, and is covered with a white coating; later, it 
may be a corroded and shapeless mass. 

The saliva flows profusely, but cannot be swallowed without 
pain, owing to the pharyngeal inflammation. Gasping and 
a hoarse voice denote that some of the acid has touched the larynx 
and caused spasmodic closure of the glottis. 

The thirst is extreme, and is accompanied by persistent retching 
and vomiting. The ejected matter is very sour and slimy, often 
bloody, and loaded with portions of the mucous membrane of 
the gullet and stomach. The face has an agonized expression, 
the eyes look hollow, the nose is pinched and cold, the skin clammy, 
the pulse feeble, the breathing difficult, and the extremities are 
convulsed. The case may end fatally in a few hours or after 
several days by asphyxia, stupor, or convulsions. When per- 
foration of the stomach is caused by rapid solution of its walls, 
the symptoms of fatal collapse rapidly develop and death is com- 
paratively painless. When death is not so sudden, and the inflam- 
matory symptoms subside, the unfortunate one has a lingering 
death of starvation from stricture of the gullet or of the pylorus, 
and an incurable dyspepsia due to destruction of the coats of the 
stomach. 

Fatal Dose. — The smallest fatal dose reported as given to an 
adult is 60 gr. (3.8 gm.). Death ensued in a child of one year 
after 20 drops. It is difficult to state the minimum limit of fatal- 
ity, owing to the fact that much depends on the part touched by 
the acid and much on the amount of food present in the stomach. 
Even the smallest amount would be permanently injurious if it 
reached the gullet, causing narrowing of the food channel. Few, 



SULPHURIC ACID 165 

if any, infants survive this poison, and of the adult cases, the 
mortality is two-thirds. 

Fatal Period. — In the infant quick inspiratory effort sometimes 
carries the poison into the larynx, and immediate death may ensue 
from spasmodic closure of the glottis. The shortest period 
recorded for the adult is one hour. Most cases die within twenty- 
four or thirty-six hours; some die from sequels after weeks, months, 
or years. 

Treatment. — Three objects are to be kept in view: first, prompt 
neutralization of the acid; second, weakening by dilution; third, 
relief of the asphyxia, which sometimes threatens life immediately. 
For neutralization, magnesia and chalk are the best, but in an 
emergency soap-suds, whiting, or wall-plaster (an impure cal- 
cium carbonate) will serve the purpose. Weak alkaline solu- 
tions of sodium or potassium carbonate may be used with caution, 
as great distress, if not injury to the weakened walls, is possible 
from the stomach distention due to the liberation of large quan- 
tities of carbon dioxid gas. All the antidotes must be given sus- 
pended or dissolved in large quantities of water or milk. In 
the absence of a neutralizing antidote water alone must be used 
immediately and in large drafts, followed by raw eggs. Should 
symptoms of asphyxia appear as a result of laryngeal implication, 
then tracheotomy or intubation must be resorted to at once. 
Morphin may be given hypodermically to relieve pain, and nutri- 
tive enemata to support life. The sequels — perforation, collapse, 
contraction of the gullet, gastritis, and impaired digestion — must 
be treated by appropriate measures as the occasion requires. 

Postmortem Appearances. — The primary pathologic changes 
found when death occurs within a few days are those of acute dis- 
organization of the structures of the mouth, gullet, stomach, 
and neighboring parts. The lips and tongue are softened and 
eroded; the throat and gullet, whitish or gray in color, the first 
effect of the acid on mucous surfaces being to coat them with 
a white paint of altered secretion and membrane; the stomach is 
brown-red, due to imbibition of altered hematin, or black from 
charring, its mucous lining loose in shreds or patches, the folds 
large and deep from swelling, sometimes softened so as to tear 
under gentle manipulation; the peritoneum may be blackened 
from perforation; the duodenum red and thickened. 

The secondary pathologic changes, seen when death follows 
after several weeks of chronic illness from some of the sequels, 
are ulceration of the gullet and contraction of its caliber from 
scars; the stomach is stripped of mucous membrane, partly or 
wholly red, its capacity much reduced by contraction, and its 
walls thickened and adherent to neighboring parts. 



1 66 NON-METALS 

Tests. — Acid Test. — The free acid, in common with other acids, 
reddens litmus, turns cochineal yellow, and decolorizes red phenol- 
phthalein. 

Barium Chlorid Test. — It is customary to test for sulphuric 
acid and the soluble sulphates by first acidulating with hydro- 
chloric acid to prevent a precipitate being produced by the salts 
of certain other acids, such as carbonic, phosphoric, and oxalic, 
and then adding a solution of barium chlorid, which throws down 
the white barium sulphate. Precipitation is hastened and per- 
fected by boiling. This reaction occurs in the sense of the fol- 
lowing equation: 

H',H-,(SOJ" + Be",Cl',Cl', = 2H',C1' + BaS0 4 . 

Ions. Ions. Ions. Molecules. 

As fast as the barium ions are neutralized by the sulphanion, 
the molecules of insoluble barium sulphate are formed and, not 
dissociating, are thrown down. This is in accordance with the 
principle: // we mix solutions of acids, bases, and salts, any of 
whose ions are capable of uniting to form an insoluble compound, 
such compound is formed and precipitated. 

Charring Test. — When sulphuric acid is applied undiluted to 
white paper it darkens, and if gently heated chars the paper; even 
if largely diluted, by heating the paper so as not to scorch it, the 
water evaporates and the acid will reach the charring-point. In 
some degree this property is shared by hydrochloric acid. 

Veratrin Test. — A drop of the free acid will turn the alkaloid 
veratrin yellow, and finally an unchanging crimson. When the 
free acid is very dilute, a fragment of veratrin is dissolved in it by 
the aid of heat, and the colorless solution, when evaporated to 
dryness in a water-bath, leaves a residue having a crimson edge, 
which persists after many hours. 

Detection. — When the acid gets upon the clothing by acci- 
dental dropping, by expectoration, or by vomiting, detection is 
comparatively easy. The strong acid will leave upon black cloth 
a damp spot which is at first red and afterward dirty brown and 
rotten. If the cloth be colored with indigo-blue, there will be no 
red stain; if with logwood and madder, the stain will be yellow. 
The stain left by the dilute acid is also red, but the spot dries out 
and is not corroded. White linen or cotton will be blackened 
and eroded. 

After many months or even years the acid may be detected in 
the spot by cutting out the piece, boiling it in i or 2 c.cm. (20-40 
drops) of distilled water, filtering, and testing with barium chlorid. 
A control experiment should be conducted simultaneously with 
a piece of the unstained cloth. Woolen textures often naturally 



SULPHURIC ACID 167 

contain sulphates, but if free sulphuric acid be present, the stain 
will turn blue litmus-paper red, will taste sour, and respond to the 
veratrin test. When some of the acid gets upon the lips, face, or 
hands, and is not instantly wiped or washed away, the burned spot 
does not blister, but turns brown, whereas with nitric acid it 
would stain yellow, and with muriatic acid there would be no 
stain whatever. The corroded skin soon sloughs, and the wound 
fills up by granulation, leaving a permanent scar. 

While it is true that the free acid is very rarely found in the 
stomach after death and "the chemical detection of a poisoning 
by nitric or sulphuric acid is, as a rule, impossible," yet in the 
majority of cases detection is rendered sure by a study of the 
surroundings, the characteristic pathologic effects, and the stains. 
Sometimes it happens that these are not conclusive, and appeal 
must be taken to a quantitative analysis. The gastric secretions 
and the food always contain some sulphates; others, such as 
magnesium sulphate, may have been given as a medicine. It is, 
therefore, necessary to estimate the total quantity of sulphates 
present, and judge if the amount be greater than normal, and if 
it can be accounted for in any other way than by the administra- 
tion of the acid itself. The mineral acids are usually separated 
from organic matter by digesting the mixture in distilled water 
for several hours. An acid reaction with litmus would point to 
free acid, and the degree of acidity could be determined by allowing 
the suspended matter to subside and then titrating a definite portion 
with decinormal sodium hydroxid, using phenolphthalein as an 
indicator. Some degree of acidity must be expected of the gastric 
contents from the presence of natural acids — hydrochloric, lactic, 
acetic, or butyric. The normal amount is so slight — not more 
than 0.3 per cent. — that any considerable showing of acid would 
be very significant. 

To get the free sulphuric acid apart from free hydrochloric or 
butyric acids and separated from the sulphates and phosphates 
the watery extract above referred to should be evaporated to 
dryness and treated with a mixture of equal parts of alcohol and 
ether. This mixture will separate the free sulphuric and phos- 
phoric acids and then by precipitation with acidified barium 
chlorid, boiling and weighing the dried precipitate of barium sul- 
phate, the amount of free sulphuric acid can be ascertained. The 
total quantity of the free acid and that combined as sulphates may 
be calculated by precipitation with barium chlorid from a definite 
fraction of the liquid containing a small amount of hydrochloric 
acid and heated to boiling. The liquid should be decanted, the 
precipitate washed, collected on a filter, dried, and weighed. One 
hundred parts of the barium sulphate precipitated represent 42 



1 68 NON-METALS 

parts of absolute sulphuric acid (H 2 S0 4 ), or 34.3 parts of sulphuric 
anhydrid (S0 3 ). By comparing the result with the small amount of 
sulphuric acid ordinarily present in a mixed meal (not more than 
0.6 gm. or 10 gr.), the fact of excess can be made out. 

The tissues rarely show free sulphuric acid, owing to its reaction 
with the phosphates. It forms sulphates with the bases and 
liberates the phosphoric acid. If the extract made with alcohol 
and ether, as stated above, when treated with ammonium molyb- 
date, should yield a yellow precipitate, this would be an indica- 
tion that free sulphuric acid had been present, unless it could be 
shown that free phosphoric acid had been given. 

As the proportion of sulphates normally present in the urine 
varies with the individual, and in the same person changes from 
day to day, no forensic importance is to be attached to the anal- 
ysis of the urine. 

Oxyacids of Sulphur. — The compounds of sulphur with 
oxygen and hydrogen are as follows: 

Thiosulphuric acid, H 2 S 2 3 , Persulphuric acid, H 2 S 2 8 , 

Hydrosulphurous acid, H 2 S 2 4 , Dithionic acid, H 2 S 2 6 

Sulphurous acid, H 2 S0 3 , Trithionic acid, H 2 S 3 6 , 

Sulphuric acid, H 2 S0 4 , Tetrathionic acid, H 2 S 4 6 , 

Pyrosulphuric acid, H 2 S 2 7 , Pentathionic acid, H 2 S 5 6 . 

The acids sulphurous, sulphuric, pyrosulphuric (Nordhausen), 
and hyposulphurous are of importance, but little is as yet known 
concerning the others. 

Thiosulphuric Acid (H 2 S 2 3 ) (Hyposulphurous). — The anion 
of this acid is (S 2 3 ) // , which differs from the sulphuric ion (S0 4 )" 
by having one oxygen replaced by one sulphur atom. This gives 
the name thiosulphuric from thion, the Greek for sulphur. It 
is commonly known only in a combination such as sodium hypo- 
sulphite (thiosulphate), Na 2 S 2 3 + 5H 2 0, or potassium hyposul- 
phite (thiosulphate), K 2 S 2 3 + 5H 2 0. These salts have the power 
of dissolving the silver salts which have escaped the action of light, 
and are largely used, under the name hypo, for fixing the image 
in photography. Sodium hyposulphite is prepared by passing 
sulphur dioxid into a mixture of sodium sulphid and caustic soda. 
Thus: 

2Na 2 S + 2 NaHO + 4S0 2 = H 2 + 3Na 2 S 2 3 . 

SELENIUM TELLURIUM 

Symbol, Se. Atomic weight, 79.2. Symbol, Te. Atomic weight, 127. 

Selenium is found associated with sulphur and, like it, has 
different allotropic forms. The amorphous variety is a black or 
dark-red solid which, kept at a temperature of 150 C, changes 



COMPOUNDS OF NITROGEN AND OXYGEN 169 

to the crystalline variety, gray, and with a metallic luster. Its 
electric conductivity varies directly as the light it receives. Tellu- 
rium forms grayish-white crystals with a metallic luster occurring 
free in nature or as tellurid of gold and other metals. Both of 
these non-metals are very rare, being found in small quantities. 
Closely allied to sulphur they form anhydrids like S0 2 and S0 3 , 
which, with water, form -011s and -ic acids, H 2 SeO s and H 2 Se0 4 , 
and H 2 Te0 3 and H 2 Te0 4 ; analogous to H 2 SO s "and H,S0 4 . " With 
hydrogen they form gases, H 2 Se and H 2 Te, which resemble H 2 S 
in their mode of formation, their odor, and their reaction with 
metallic solutions, but which are less stable, with odors more 
disgusting than hydrogen sulphid. All of them on combustion 
yield dioxids. 

Sulphur Group. — A trinity corresponding to the halogens is 
formed by sulphur, selenium, and tellurium. They are divalent 
and sometimes tetravalent, hexavalent, or octavalent. Their 
atomic weights are S., 32; Se., 79.2; Te., 127. The mean is 79.5, 
which is nearly the atomic weight of Se. Their properties are 
similar, but vary in the order of their atomic weight. 

COMPOUNDS OF NITROGEN AND OXYGEN 

Nitric Acid (HXO s ) (Aqua Fortis). — Occurrence. — Xitric 
acid is not free in nature. As the result of the oxidation of nitrog- 
enous animal matter potassium and sodium nitrate are widely 
disseminated, especially in guano deposits. The nitrates are also 
to be found in traces in rain-water and in the surface wells of towns. 

Preparation. — Either potassium or sodium nitrate will yield 
nitric acid when distilled with sulphuric acid. Though nitric acid 
is the stronger acid, yet, owing to its volatility, it gives place to sul- 
phuric acid, which is non-volatile. This is according to a general 
law: that, given the materials to form a volatile compound, it is 
always formed and passes off in vapor. 

NaNO s + H 2 S0 4 = XaHS0 4 + HN0 3 .' 

Sodium nitrate. Monosodium sulphate. 

Physical Properties. — Pure nitric acid is a colorless liquid, 
boiling at 86° C. (186. 8° F.) and solidifying at -47 C. (-52. 6° 
F.). The commercial article is yellow and of two different 
strengths: single aqua jortis, specific gravity 1.25, containing 39 
per cent, of HXO s , and double aqua jortis, specific gravity 1.4, 
with 64 per cent, of HNO s . Red juming nitric acid has a specific 
gravity 1.6 and is obtained by distilling at a high temperature or 
by adding reducing organic matter during distillation. 

Chemical Properties. — Xitric acid takes rank with the strong- 
est acids because it dissociates hydrion to a great degree. For 



170 NON-METALS 

the same reason its conductivity as an electrolyte is high. It attacks 
and dissolves all the metals except gold and the platinum family. 
Its neutral salts, the nitrates, are all soluble in water. The com- 
pound formed with albumin is insoluble. Nitric acid does not 
keep pure long, the sunlight alone having power to decompose it 
into oxygen, water, and lower nitrogen oxids of a yellow color 
which dissolve in the water. 

2HNO3 = N 2 4 + H 2 + O. 

Nitrogen tetroxid. 

The strong tendency of nitric acid to form ions makes easy 
this production of water. The hydrion H", stimulated by sun- 
light, breaks up the anion (N0 3 )' because it appropriates the 
oxygen ions forming undissociated water molecules. The velocity 
with which the oxidizing effect is produced is accelerated by the 
presence of N 2 4 acting as a catalyzer. Hence for high oxidation 
effects the red fuming acid is preferred. 

Most of the value of nitric acid, chemically, is due to this insta- 
bility, which it shares with ozone and hydrogen dioxid. In the 
presence of substances that can be oxidized this power is exerted 
to a marked extent, red fumes of lower oxids arising. In its 
reaction with metals the hydrogen is not always liberated, but is 
taken up by the oxygen to form water, thus causing the forma- 
tion of the reddish nitrous fumes. It is a monobasic acid disso- 
ciating as H'^NOg)' and yielding but one class of salts, such 
as Na*, (N0 3 )'. 

Technical Uses. — Metal workers use this acid for etching and 
for cleansing preparatory to gilding and lacquering. Of late 
years it has had a great extension of employment in the making 
of various organic nitrocompounds, such as gun-cotton, celluloid, 
nitroglycerin, dynamite, and picric acid. Dyers, hatters, and 
chemists have need for it. 

Medical Uses. — It is used in medicine as a valued caustic only 
under the official name acidum nitricum, of specific gravity 1.40, 
containing 68 per cent. HNO s . On prolonged exposure to light 
and air the lower oxids of nitrogen are developed and impart 
a yellow color. It is then called nitrosonitric or fuming acid, 
useful as a reagent for biliary coloring matter in Gmelin's test. 
As an escharotic it corrodes organic matter by oxidation, not by 
carbonizing, as sulphuric acid does. Animal matter is turned 
a deep yellow, the color of picric acid. Albumin is coagulated by 
it, and if the acid be strong the white coagulum turns the char- 
acteristic yellow. It gives promptly the acid reaction with litmus 
and other color indicators. 



COMPOUNDS OF NITROGEN AND OXYGEN 17 1 

Acidum nitricum dilutum (U. S.), specific gravity 1.054, con- 
taining 10 per cent. HN0 3 , is the only form suited for internal 
administration. The dose is 5-15 Vf[ (0.33-1 ex.), largely diluted. 

Incompatibles. — Alkalies and alkaline earths and their car- 
bonates, calomel, and other mercurous salts. 

Toxicology. — Although widely used in the arts, this acid fig- 
ures as a poison much less frequently than does sulphuric acid. 
History shows that most of the cases are suicidal, and when the 
intent is homicidal, the victim is either a child or an adult ren- 
dered unconscious by sleep or drunkenness. It would not be 
possible to give it in food or medicine without detection. 

Symptoms. — There is no important difference from the symp- 
toms produced by sulphuric acid and already described (p. 164), 
with the exception of the color of the mouth and lips, which, with 
nitric acid, is intensely yellow, though at first the parts are blanched 
and white. There are intense pain, vomiting, thirst, and great 
depression. Eructations of gas are frequent and distressing, due 
to its direct development by the action of the acid on organic sub- 
stances. 

Fatal Dose. — Three niu* drams by the mouth in adults have 
destroyed life, but a much smaller quantity would suffice to cause 
fatal suffocation from spasmodic closure if it were to enter the 
larynx, as it is likely to do in children. 

Fatal Period. — The average duration of life is about twenty- 
four hours; the shortest time reported in the case of an adult 
was an hour and three-quarters, while a case is recorded of an 
infant who died in a few minutes. In some cases death has been 
delayed for weeks, months, or years, the remote effects of the 
poison then proving fatal. 

Treatment. — The extraordinary energy and rapidity of action 
of nitric acid make it difficult to administer antidotes with sufficient 
promptness to be of much help. It is always advisable to use 
chalk, whiting, magnesia in milk, soapsuds, and eggs as anti- 
dotes, with the hope of neutralizing some free acid. The method 
is the same as for sulphuric acid and for the corrosive acids gen- 
erally. In all there is instant local death of parts struck by the 
poison, rapidly followed by inflammation of surrounding viscera. 
Our antidotes cannot restore the tissues to health, nor can they 
diffuse into distant parts fast enough to be of much avail. The 
symptoms must be treated on general principles as they appear. 

Postmortem Appearances. — All the parts to which the acid is 
applied present the various marks of erosion — in places harden- 
ing and thickening, in others ulceration and sloughing, general 
pulpiness, shreddy mucous surfaces denuded of membrane, and 
perforations of the gullet, the stomach, or the intestine. The 



172 NON-METALS 

most characteristic pathologic change is the permanent citron- 
yellow or orange-brown color of the tissues acted on. 

Tests. — Even when very largely diluted — that is, 0.2 per cent. — 
the acid reddens litmus (see Tests for Free Mineral Acids, p. 138). 

Copper Test. — Poured upon slips of copper and gently heated, 
effervescence occurs and red-brown vapors arise that redden moist 
litmus-paper. If the amount of nitric acid be small, the color of 
the fumes may not be noticed, and a more delicate test is required. 
By holding in the vapors a piece of paper moistened with potas- 
sium iodid and starch paste a blue color develops. 

Brucin Test. — Upon a crystal of brucin a drop of nitric acid 
strikes a blood-red color; upon morphin an orange hue, with 
orange-colored fumes. 

Ferrous Sulphate Test. — Upon a white porcelain surface put 
a few drops of the suspected liquid, a drop of sulphuric acid, and 
a crystal of ferrous sulphate; the crystal turns dark-green, and 
finally brown. Even the combined acid in nitrates yields the 
same proof with any of the above tests, provided pure sulphuric 
acid is first used to free the nitric acid. If eggs have been given 
as an antidote, the nitric acid must be taken from the albumin by 
means of a solution of potassium carbonate; the resulting soluble 
nitrate can then be treated by equal parts of sulphuric acid and 
water before applying the above tests. 

Detection. — On inspection the stains left on the clothing will 
be found dry and partaking of the same citron-yellow change 
found on the skin or other animal tissue touched by this acid. 
The yellow stain produced by tincture of iodin is discharged by 
potassium hydroxid or by ammonia-water, but the nitric-acid 
stain is indelible; ammonia and the alkalies only intensify it to 
an orange hue. If the piece of stained cloth be boiled in some 
distilled water, litmus-paper will reveal the acid reaction. When 
the acid liquid is neutralized with potassium carbonate, filtered 
and evaporated to dryness, crystals of potassium nitrate form. 
When these crystals are dissolved in water and a drop of pure 
sulphuric acid is added, the nitric acid is set free and strikes a 
blood-red color with brucin, yields ruddy fumes with copper 
turnings, or responds to the ferrous-sulphate test for nitric acid. 

If the vomited matters be decidedly acid, the acidity should be 
measured by titration with decinormal solution of sodium hy- 
droxid. The resulting sodium nitrate can then be tested by 
treating with sulphuric acid and applying any of the tests above 
mentioned. 

As nitrates are not constituents of ordinary food or of the ani- 
mal tissues, it is proof enough if these be found in any amount 
above a trace. It is not necessary to make a quantitative 



COMPOUNDS OP NITROGEN AND OXYGEN 1 73 

analysis. The vomited matters or the tissues should be extracted 
with boiling distilled water and potassium carbonate and then 
filtered. Crystals of potassium nitrate are obtained on evapora- 
tion which respond to all the tests given above for nitrates. 

Fumes of Nitric Acid. — The emanations of nitric acid are a 
mixture of nitric acid vapor with various lower oxids, all of them 
offensive and irritating to the air-passages. In the industries 
mentioned above as making use of this acid these vapors may do 
great harm if the processes be not carried on in closed vessels 
and the noxious fumes passed into milk of lime. The habitual 
breathing of air containing only a small amount frequently leads 
to severe chronic bronchitis with general impairment of health. 
In the annals of toxicology cases of acute poisoning are reported 
from chemists suddenly inhaling the fumes rising when a carboy 
of the acid has been accidentally broken. The symptoms are like 
those of capillary bronchitis. 

In fatal cases there is found usually congestion of the larynx, 
trachea, and bronchial tubes, and sometimes edema of the lungs 
or effusion of blood. Although the effects appear to be mainly 
those of direct irritation, some cases show inflammatory changes 
in the lining of the right auricle. Acute cases should be treated 
by fresh air and inhalations of ether to relieve the sense of con- 
striction. 

Nitromuriatic Acid (Acidum Nitrohydrochloricum, U. S.). — 
By mixing i part of nitric and 3 parts of hydrochloric acid the 
commercial aqua regia is prepared. This is an unstable liquid, 
evolving free chlorin and other gases, and eventually becoming 
much weaker than when first made. The nitric acid oxidizes the 
hydrochloric, taking its hydrogen to form water and liberating 
chlorin and nitric oxid: 

HC1 + HNO3 = CI + N0 2 + H 2 0. 

The nascent chlorin will act on gold and platinum, forming 
soluble chlorids. It dissolves all the metals, including gold and 
platinum, and oxidizes iodin, phosphorus, and sulphur. It coagu- 
lates albumin, turns it yellow, and finally dissoLves it, as it does 
all vegetable and animal substances, with the production of 
ruddy fumes. 

Acidum Nitrohydrochloricum Dilutum (U. S.).— Dose, 5-8 TIT 
(0.30-0.50 c.c). While the dilute acid is given internally as a medi- 
cine, the concentrated acid is an exceedingly corrosive poison, the 
symptoms and postmortem appearances of which differ from those 
of nitric acid in degree only. The antidotes are the same as for 
the other mineral acids. 



174 NON-METALS 

NITROGEN OXIDS 

In nature certain bacteria growing in nodules on the roots of 
leguminous plants have the power of uniting the nitrogen and 
oxygen of the air, enriching the soil with nitrates. By passing 
streams of electric sparks through the air an acrid smell is per- 
ceived and red vapors arise. These are nitrogen trioxid and 
tetroxid, and, when washed down with alkaline fluids, nitrites and 
nitrates are formed. In another place, as illustrating the law of 
multiple proportions, the following five compounds have been 
mentioned: 

Nitrogen pentoxid, or nitric anhydrid N 2 5 . 

Nitrogen tetroxid, or hyponitric acid N0 2 or N 2 4 . 

Nitrogen trioxid, or nitrous anhydrid N 2 3 . 

Nitrogen dioxid, or nitric oxid NO or N 2 2 .. 

Nitrogen monoxid, nitrous oxid, or laughing gas N 2 0. 

Nitrogen pentoxid, N 2 5 {anhydrous nitric acid), can be 
prepared by removing water from 2 molecules of nitric acid, 
H 2 N 2 6 , which then becomes N 2 5 . Nothing will serve but the 
most powerful dehydrating substance, phosphorus pentoxid, P 2 O s . 
The mixture distilled yields the nitric anhydrid as a white crystal- 
line substance. This easily decomposes by reversing the process, 
by which it was made, taking up the elements of water. 

N 2 5 + H 2 = H 2 N 2 O e or 2HNO3. 

Nitrogen Dioxid (N 2 2 ) {Nitric Oxid).— It has been stated 
that a number of lower oxids, reduction products, are formed 
by the action of HNO s on copper or other metals. They vary 
according to the concentration of the acid, the nature of the metal, 
and the temperature. The one yielded most easily when copper 
clippings are used as the metal is NO or N 2 2 . The reaction is 
as follows: 

3 Cu + 8HNO3 = 3 Cu(N0 3 ) 2 + N 2 2 + 4 HO. 

Copper nitrate. Nitrogen dioxid. 

The first brown vapors are made colorless in passing through 
the pneumatic trough. This colorless gas, N 2 2 , is feebly solu- 
ble. It neither burns nor supports combustion. If collected in 
a bell jar and oxygen admitted, there is instant union, with the 
formation of reddish-brown nitrogen tetroxid: N 2 2 + 2 = N 2 4 . 
This red gas is dissolved by the water which rises in the jar as 
the volume of the residual gas diminishes. Nitrogen dioxid is 
taken up by solution of ferrous sulphate, which turns dark browrx 
(see Tests for Nitric Acid, p. 172). 



COMPOUNDS OF NITROGEN AND OXYGEN 



175 



Nitrogen Tetroxid (N 2 4 ) {Nitrogen Peroxid, Hyponitric 
Acid). — The brown-red fumes formed by the union of N 2 2 with 
oxygen in the air can be condensed to a yellow liquid which 
loses color with an accompanying decline of temperature. It 
solidifies at — 12 ° C. ( — 10.4 F.) into colorless crystals. A study 
of the vapor density shows that the dark-red gas at 100 ° C. 
(212 ° F.) has the formula N0 2 , but the almost colorless gas 




Fig. 54. — Apparatus for generating nitrogen dioxid. 



below o° C. (32 F.) has the formula N 2 4 or 2(N0 2 ). At in- 
termediate temperatures the gas is a mixture of the two forms. 
As stated above, it is the final product of electric discharges in 
the air, and dissolved in water it decomposes into nitric and 
nitrous acids. 



N 2 4 



+ 



H 2 



+ 



HNO,. 



HNO3 

Nitric acid. Nitrous acid. 

Toxicology. — In the manufacture of gun-cotton, oil of vitriol, 
oxalic acid, nitrobenzol, picric acid, and in metal working and 
gilding, the deoxidized nitric acid is the source of offensive, irri- 
tating, and, when very strong, deadly vapors, of which the chief 
constituent is nitrogen tetroxid. Workmen breathing it habitu- 
ally suffer from chronic bronchitis with cough, suffocative attacks, 
dysuria, and delirium. These symptoms may culminate in death. 

Nitrous Acid (HN0 2 ).— On reducing potassium nitrate with 
lead a salt is formed having less oxygen: potassium nitrite. 



KNO, 



+ 



Pb 



KNO, 



PbO. 



Nitrate. Nitrite. 

The nitrite being soluble can be removed by water from the 
insoluble lead oxid. Again, by carefully heating KN0 3 it loses 
oxygen, yielding the nitrite: 



2 KNO, 



O, 



+ 



2KN0 2 . 



176 NON-METALS 

The acid, as such, cannot be liberated from this salt by the 
action of sulphuric acid; it is too unstable at ordinary temperatures, 
but brownish vapors arise of nitrogen trioxid, N 2 3 , sometimes 
called nitrous anhydrid, which decomposes into N0 2 + NO. It 
condenses to a dark indigo-blue liquid which boils at o° C. (32 F.) 
and solidifies at — 82 ° C. (—115. 6° F.). This brown gas passed 
into water forms a blue solution containing some nitrous acid, 
but soon decomposes into nitrogen dioxid, nitric acid, and water. 

3 HN0 2 = N 2 2 + HNO3 + H 2 0. 

Nitrous acid. Nitrogen dioxid. Nitric acid. 

Tests for Nitrites. — Salts having the ion (N0 2 )' give the same 
brown reaction with ferrous sulphate as that referred to among 
the tests for nitric acid; but when treated with sulphuric acid the 
nitrites are peculiar in yielding the brown vapors of N 2 3 . Nitrites 
deoxidize and decolorize instantly the purple solution of potas- 
sium permanganate. 

Nitrogen Monoxid (N 2 0) (Nitrous Oxid, " Laughing Gas").— 
Preparation. — By gradually heating ammonium nitrate to 250 
C. (482 ° F.) in a retort the crystals melt and easily decompose, 
water being formed and a permanent gas generated, capable of 
being collected over hot water or mercury. 

NH 4 N0 3 = N 2 + 2 H 2 0. 

Ammonium nitrate. Nitrous oxid. 

To purify the product for inhalation the gas should be passed 
through warm solutions of sodium hydroxid and ferrous sul- 
phate. 

Properties. — Nitrous oxid is a colorless gas with a sweetish 
odor and taste; it is soluble in an equal volume of water and readily 
liquefied by pressure. The liquid is a useful refrigerating agent. 
Nitrous oxid does not burn, but yields oxygen to burning sub- 
stances, supporting the combustion of carbon and phosphorus 
almost as well as oxygen. It does not part with its oxygen to 
burning sulphur when the flame is small, but with a large flame 
forms S0 2 just as would free oxygen. It does not break up and 
give oxygen to the body at the living temperature. 

Physiologic Effect. — Nitrous oxid gets the name laughing gas 
from the gay intoxication first caused by inhaling it mixed with 
air. When pushed beyond this hysteric stage or when inhaled 
pure the effects are those of a transient narcotic. 

Toxicology. — As the organism does not have the power to 
utilize the oxygen in this gas when it is inhaled, along with anes- 
thesia, some asphyxia is produced, which in healthy subjects can 
be borne long enough for short operations, such as tooth extrac- 
tion. To prolong its effects with safety oxygen must be mixed 



PHOSPHORUS 177 

with it. Very rarely its administration has been fatal; some heart 
weakness is responsible for this result in most cases. 

Hyponitrous Acid (HNO). — This substance can be obtained 
in white crystalline scales which readily explode, owing to their 
instability. Dissolved in water, it soon evolves the gas nitrogen 
monoxid, N 2 0. Sodium hyponitrite is a permanent salt made by 
the reduction of sodium nitrite with metallic sodium in amalgam: 

NaN0 2 + 2Na + H 2 = NaNO + 2 NaHO. 

Sodium nitrite. Sodium hyponitrite. 

PHOSPHORUS 

Symbol, P. Atomic weight, 31. 

Occurrence. — This element is not found free in nature, occur- 
ring in combination mainly as phosphates in various minerals of 
the soil and in the structure of plants and animals. It was first 
discovered as a constituent of human urine. 

Preparation. — Phosphorus is made from bone-ash, Ca 3 (P0 4 ) 2 , 
by heating it with carbon and sand in an electric furnace. This 
reduces the bone phosphate of calcium to elementary phosphorus, 
which is distilled and run into molds under warm water to make 
stick phosphorus. 

2Ca 3 (PO) 4 + 10C + 6Si0 2 = 10CO + 6CaSiO + P 4 . 

Calcium phosphate. Silicon dioxid.. Calcium silicate. 

Properties. — The ordinary crystalline or waxy form usually 
occurs in translucent cylinders which cut like wax, and when 
kept under water turn yellow and become coated with a thin 
white crust. As it oxidizes in the air it should be kept under 
water that has been well boiled to expel dissolved oxygen. It 
takes fire at 50 ° C. (122 ° F.), a temperature easily reached by 
friction between the fingers, hence the caution to handle it with 
forceps. If it should take fire in the hand, it will burn severely, 
and at the same time more or less of the poison will be absorbed. 
The poison in the burn should be made inert by a lotion of chlo- 
rinated soda or a paste of chlorinated lime. 

It has the odor and taste of garlic, is very sparingly soluble 
in water, slightly soluble in alcohol and glycerin, but freely so in 
carbon bisulphid, almond oil, and ether. Under water at 44.5 ° C. 
(iii° F.) it melts to an oily fluid, which can be run into cylindric 
molds. Exposed to the air, white fumes of its lower oxid, P 2 3 , 
are evolved, and in the dark emit a feeble light. Black and white 
phosphorus are modifications of no practical importance. 

Red phosphorus is an allotropic form made by heating the 
waxy variety in a closed vessel without air for thirty-six hours. 



178 NON-METALS 

It is a red-brown crystalline powder, insoluble in the solvents for 
waxy phosphorus, does not oxidize in air, is not luminous, need 
not be kept under water, and requires a much higher temperature 
to inflame it than does the waxy form. It does not take fire 
unless heated to 280 ° C. (536 ° F.). The pure red phosphorus 
is not poisonous, but the commercial article sometimes contains as 
much as 0.6 per cent, of the waxy, poisonous form. 

The hicijer matches commonly sold are tipped with waxy or 
poisonous phosphorus mixed with potassium chlorate, sand, and 
glue, but the " sajety-match" is tipped with potassium chlorate 
and antimony sulphid without phosphorus. In order to light the 
"safety-match" it must be rubbed upon the side of the containing 
box, which is covered with a thin coat of red or non-poisonous 
phosphorus, mixed with sizing. 

There is some resemblance between nitrogen and phosphorus 
in their corresponding compounds with hydrogen, both forming 
gaseous compounds, NH 3 and PH 3 ; with oxygen, N 2 3 , N 2 5 and 
P 2 3 , P 2 5 . Like nitric acid, HNO s , there is a metaphosphoric 
acid, HP0 3 . 

The molecular weight of phosphorus is 124, which is four 
times the atomic weight, 31; hence there must be four atoms in 
its molecule. 

Pharmaceutic Preparations. — Phosphorus is usually given 
in a pill-mass with cocoa-butter or some other excipient and coated 
with sugar or gelatin to prevent oxidation. The presence of the 
free phosphorus can be shown by cutting the pill open and ex- 
posing the mass to gentle heat in the dark. It should "phos- 
phoresce" — i. e. y emit light. Oleum phosphoratum is a solution 
in almond oil of 1 per cent, strength. Spiritus phosphori is a 
solution in absolute alcohol of about 0.1 per cent, strength. An 
ethereal solution is also used. 

Toxicology. — As alkaline and earthy phosphates, it is a 

constituent of the tissues and fluids of the human body; it is 

found largely in the bones as calcium phosphate and in the nervous 

centers as a compound with fat and albumin. Ever since it was 

first used to tip lucifer matches its poisonous properties have been 

known; indeed, on the Continent of Europe it has been the favorite 

rat poison. While the other active poisons are guarded by law 

from general distribution, this one is easily obtained as the heads 

of matches and as "rat-paste, " which contains from 1 to 4 per cent. 

of phosphorus mixed with oil, flour, sugar, and coloring-matter. 1 

It is rarely used by homicides, but frequently by suicides, and 

1 Coster's Rat and Roach Exterminator contains 2.13 per cent, of phosphorus, 
and though the buyer is assured by the label that it is "not poisonous, " 2 fatal cases 
have been reported from taking it. Parson and Co.'s Vermin Exterminator has 0.4 
per cent, of free phosphorus. 



PHOSPHORUS 179 

sometimes children ignorantly eat the paste or suck the heads of 
matches. More than half the death cases are children. Of the 
adults, nearly all are suicidal, a few only being accidental and 
none criminal. In spite of the garlicky taste and smell, it could 
be given in coffee, the more easily if at the same meal onions or 
garlic had been eaten. 

Symptoms. — If the phosphorus be taken in lumps, the effect is 
not proportionate to the weight. To be fully effectual it must 
be dissolved or finely divided, as it is in the rat-pastes and pill- 
masses. 

The cases of poisoning are often referred by their symptoms 
to one of the three classes established by the researches of Tar- 
dieu — a common form, showing symptoms of local irritation and 
jaundice; a hemorrhagic form like scurvy, in which jaundice and 
effusions of blood occur; and a nervous form, in which jaundice 
is accompanied by creeping sensations, cramps, drowsiness, delir- 
ium, and convulsions. 

Nearly 90 per cent, of the cases suffer from acute irritation 
followed by jaundice and profound blood changes. Complaint is 
made that the substance taken had the taste and odor of garlic. 
Sometimes violent pain in the throat, gullet, and stomach is ex- 
perienced immediately, accompanied by vomiting and purging. 
The breath is phosphorescent, and the ejected matters may be 
bloody, garlicky in odor, and emit light when stirred in a shallow 
dish. In a large number of cases there is an interval of several 
hours between the taking of the poison and any symptom what- 
ever. 

Death from collapse may come at this early stage, but usually 
the irritation abates and jaundice sets in after a period of com- 
parative comfort. This quiet interval usually lasts from two to 
three days, but it may be only one day in length or be prolonged 
for several weeks. The jaundice portends more or less profound 
blood changes. In addition to the general effects wrought by the 
biliary matters in the circulation there will be the toxic symp- 
toms, caused by the presence of phosphorus derivatives. Given 
in detail, there will be yellowness of skin and conjunctiva and 
tenderness over the liver, with an increased area of hepatic dul- 
ness. Headache, insomnia, and itching eruptions of the skin are 
common. The urine is saffron-yellow or olive-green in color from 
the presence of bile-pigments, scanty, albuminous, bloody, con- 
taining tube-casts and occasionally leucin and tyrosin. Extreme 
weakness culminating in heart failure is a characteristic due to 
the degenerations of the muscular tissue, including the heart. 
These stormy signs soon culminate in delirium, convulsions, 
coma, syncope, and death. 



180 NON-METALS 

In a certain proportion of cases, not necessarily fatal, the toxic 
effects on the blood and its vessels are made conspicuous by the 
hemorrhages which accompany the jaundice. Blood may be 
effused under the skin in spots or pass out by one or more of 
the mucous channels. Hemorrhage has occurred from the nose, 
mouth, bowels, kidneys, and bladder all at once. Women will 
have uterine hemorrhage, and if pregnant, will abort, with alarm' 
ing flooding. Anemia and exhaustion reach an extreme stage, 
and delirium ending in death may supervene after months have 
elapsed since the administration of the poison. Even when the 
direct influence of the poison has passed away and life is no longer 
threatened, there may be persistent debility and local palsies. 

The rarest form of acute poisoning is that in which the nervous 
phenomena are the most conspicuous. This form is likely to 
occur when the case is one of inhalation of fatal quantities of 
phosphorus vapor. In the preparation of " rat-paste," or in the 
making of matches, the materials may be accidentally heated so 
as suddenly to evolve large quantities of phosphorus vapor. The 
effects are fainting attacks, succeeded by profound prostration 
with extreme muscular weakness. 

Emphasis must be laid upon the variety of symptoms, permit- 
ting of many different clinical pictures and also upon their insidi- 
ous development. There can be but little doubt that at one time 
many cases were incorrectly diagnosed as acute yellow atrophy 
of the liver. This is not surprising, as the history of the case 
after the liver symptoms appear is the same as in acute yellow 
atrophy, even to the contraction of the organ itself. In a very 
small proportion of cases surviving a week jaundice does not 
occur. Casper reports a case that lived for twelve hours, the 
only marked symptoms being one act of vomiting and a garlicky 
odor of the breath, which was luminous in the dark. 

Fatal Dose. — In the treatment of nervous diseases the usual 
dose is 5V gr. (0.0013 gm.) thrice daily, but some persons can 
bear gradual increase to as much as J gr. (0.016 gm.). It would 
be risky to begin with these maximum quantities, as the subjects 
of nervous diseases are usually very susceptible. A lunatic died 
from the effects of 0.0116 gm. (less than -§- gr.). 

A healthy adult would have his life put in jeopardy from 1 gr. 
taken in a finely divided form, such as the pill, paste, or the match- 
head. A child is reported to have died from sucking the heads 
of two matches, containing about 5V gr. of phosphorus. On the 
other hand, there has been recovery after ten packages had been 
sucked. 

Fatal Period. — Death has occurred in less than one hour, but 
the duration of life is very diverse in different cases. Some die 



PHOSPHORUS l8l 

in four hours; three-fourths of the cases die within a week; some 
cases become chronic, the patient dying a lingering death after 
many months. * 

Treatment. — In considering the best remedial procedures it 
must be noted that great differences have been observed in the 
time of onset of the symptoms. In the majority they commence 
after an interval of from two to six hours; in a few they are de- 
scribed as immediate; in four-fifths they come on within six hours. 
In every case presenting a history of a poisonous dose the treat- 
ment should be instituted at once, instead of waiting for the symp- 
toms to appear. There is need for instant evacuation by the 
stomach-tube, and washing out of the stomach with a solution 
of potassium permanganate of the strength of 0.5 to 1 per cent. 
(about 4 gr. to 1 fl. oz.), leaving about a pint in the stomach. 
This antidote has a chemical reaction with the phosphorus, by 
which the latter is said to be changed to harmless compounds. 
Potassium permangante oxidizes the phosphorus, forming phos- 
phoric acid and phosphates, itself changing to manganese dioxid. 
In the absence of a stomach-tube the antidote should be given — 
4 gr. in 1 oz. of water — frequently repeated. The permanganate 
is in part reduced by the organic substances of the food, and hence 
the necessity of giving it in excess, although in a dilute solution to 
avoid gastric irritation. Diluted hydrogen peroxid (1-3 per cent.) 
as an oxidizing agent is used for the same purpose as the potas- 
sium permanganate and is more uniformly beneficial. Perhaps 
the most efficient oxidizing antidote is a mixture of the two accord- 
ing to the method given (p. 88, foot-note). 

Copper sulphate is often recommended as an antidote. When 
its solution is mixed with phosphorus in a test-tube, the phos- 
phorus is seen to change instantly to black copper phosphid, 
which is not injurious. There is one drawback to its use. In the 
quantities recommended and needed for full antidotal effect (3 gr. 
frequently repeated) the copper salt is a decided irritant and is 
likely to aggravate the gastro-enteritis or set up a violent one of 
its own. 

Another antidote honored by text-book commendation is tur- 
pentine. It is said to combine with the phosphorus to produce 
phosphoroterebinthinic acid, a non-poisonous solid. To be effi- 
cient the article must be an old acid sample, and some enjoin that 
the French article alone is of any value. As old French turpen- 
tine is not the kind kept officially by druggists, it is practically 
out of the question. 

After potassium permanganate or hydrogen peroxid has been 
freely used for the phosphorus in the stomach, evacuation of the 
bowels should be secured by the use of some old turpentine that 



182 NON-METALS 

has been kept for a long time on the shelf in doses of J fl. dr. 
(1.90 c.c), given in an emulsion with mucilage every half hour. 
As the phosphorus tends to adhere to the mucous folds of the 
small intestine it is advisable to maintain purgation by giving the 
turpentine for several days. 

Postmortem Appearances. — The general toxic effect of phos- 
phorus is to induce a wide-spread degeneration of glandular and 
muscular tissue. This degeneration consists in the formation of 
fat in place of the true cellular tissue. It is presumable that those 
cases of death in which no change has been found postmortem 
would have yielded a different report if the microscope had been 
used to aid the naked eye. The stomach may be free from signs of 
disease, although, as a rule, there will be a fatty degeneration of 
the epithelial cells, with thickening of the mucous membrane, due 
to enlargement of the glands and an occlusion by large granular 
cells. This condition obtains in the intestines and is often asso- 
ciated with hemorrhagic foci and minute inflamed areas. These 
appearances are found also in diseases due to septic conditions of 
the blood. 

Even at an early period the liver is the seat of fatty degenera- 
tion. If seen early, it may be enlarged, yellow, deficient in blood, 
and present a mottled section. Under the microscope the hepatic 
cells are found to lack definition and to be granular or filled with 
large fat-globules. When death follows a chronic history, the 
liver may be found atrophied and the changes more profound. 

The capsule of the kidney is easily stripped. Under it are 
found hemorrhagic patches. The organ itself is enlarged, and 
its epithelial cells and vascular walls are infiltrated with granular 
fat. 

The transverse stripes of the muscular fibers of the heart are 
replaced by fat, a form of change seen in the muscular system 
generally. If the case has been one of the hemorrhagic type, 
there will be extravasations of blood in the tubules of the kidney, 
in the endocardium, the peritoneum, the pleura, the mediastinum, 
and many other places. 

Chronic Poisoning. — Weakly individuals working in match 
factories, or makers of phosphorus itself, whose occupation re- 
quires that they must inhale phosphorus fumes daily, become the 
subjects of "lucifer disease" or "phosphorus necrosis." After 
several weeks or months obstinate toothache is felt, and when the 
tooth is extracted the gum does not heal, but retracts, leaving a 
suppurating bony surface. Pieces of bone come away, and the 
disease-process in the marrow and in the periosteum spreads to 
new areas, other teeth and their sockets become involved, and 
greater portions of bone necrosed. Accompanying the local 



PHOSPHORUS 



183 



"' :'\ 



mischief, partly caused by it and also aggravating it, is a general 
disturbance of health characterized by anemia, pallor, weakness, 
hectic fever, diarrhea, septicemia, purpura, sometimes ending in 
death by exhaustion. These symptoms may be prevented by 
dental inspection of workmen and filling of all carious spots on the 
teeth, by the circulation of fresh air, by the frequent and sys- 
tematic use of mouth-washes of sodium bicarbonate, and by 
the prompt exclusion of any one showing significant symptoms. 

The use of " safety-matches" and varieties substituting the red 
or non-poisonous form is spreading, and, with better hygienic 
measures, bids fair to remove this disease from the bills of mor- 
tality. 

Tests. — The tests for phosphorus are its peculiar odor, its 
luminous appearance in the dark, and the power of reduction 
possessed by it over silver nitrate. 

Detection. — The garlicky odor is sus- 
picious, but may be masked by articles of 
food having a similar odor, such as onions. 
If the room be darkened, the breath will 
shine faintly and phosphorescent spots will 
be seen upon the lips or clothing. The 
vomited matters or the urine, if put into a 
test-tube, acidulated with sulphuric acid, 
and gently heated, will evolve luminous 
fumes. A piece of white paper molded as 
a lid to the tube (Fig. 55) should be wet 
with a drop of a strong solution of silver 
nitrate. The phosphorus vapor will cause 
the metallic silver to be reduced as a black 
spot on the paper. To prove that this is 
not produced, by hydrogen sulphid, the 
same test should be repeated after adding 
some lead acetate to fix the hydrogen sul- 
phid in the liquid, or a plug of absorbent 
cotton wet with lead acetate may be put 
in the neck of the tube. When the phos- 
phorus is present in minute quantities, it 
will not be evident by this test unless per- 
formed by the careful method of Mitscher- 
lich. 

Mitscherlich's Test. — The suspected material is put into 
a flask (c, Fig. 56) and acidulated with sulphuric acid to prevent the 
escape of ammoniacal vapors. When heated gradually by the 
sand-bath the phosphorus vaporizes, and is conducted by a long 
delivery tube to a glass Liebig condenser, d, kept cold by water 



_ Fig. 55. — Apparatus for 
testing phosphorus vapor with 
silver nitrate. 



1 84 



NON-METALS 



circulating around the inner tube. The room being totally dark, 
flashes of light and shining clouds appear in the inner tube at the 
point where the phosphorus vapors are condensed by their cold 
surroundings. The odor of the distillate is alliaceous. 

The tube being vertical, the condensed phosphorus will pass 
down into a receiver, e, where it may be converted to phosphoric 
acid by the action of nitric acid. The phosphoric acid precipitated 
by magnesian mixture, collected, ignited, and weighed, will deter- 
mine the quantity of phosphorus. 

If no luminosity has been observed after distilling one-third of 
the material, the remainder may be subjected to a more searching 
test. The end of the exit tube of the flask should be detached 




Fig. 56. — Mitscherlich': 



test for phosphorus: a, Generator for CO2; b, wash-bottle; c, suspected 
material; d, condenser; e, receiver for distillate. 



from the condenser at d, and immersed in a solution of silver nitrate. 
The contents of the flask, c, are again heated, while a continuous 
current of carbon dioxid from the generator, a, washed in b, 
passes through, slowly carrying the phosphorus unoxidized into 
the silver nitrate, precipitating black silver phosphid, and leaving 
some phosphoric acid in solution. Should no black deposit appear, 
the phosphorus may be assumed to be absent. The silver phosphid 
collected on a filter and washed is suspended in water, and intro- 
duced into the hydrogen apparatus employed in the phosphin test 
described below. The greenish flame is seen even when the 
quantity is very minute. 

Fallacies. — Deductions based upon the detection of phosphoric 



PHOSPHORUS 



185 



acid in the distillate when luminosity and free phosphorus have 
not been obtained may be erroneous. The phosphoric acid may 
have been brought over by mechanical action. 

Interferences. — It can be performed in an organic mixture, but 
not in the presence of certain chemicals, such as iodin, calomel, 
and corrosive sublimate. The light will not show in the vapor 
of turpentine, which may have been given as an antidote. It is 
not perceived, should alcoholic or ethereal vapors arise from the 
same mixture. Ammonia, chlorin, hydrogen sulphid, sulphur 
dioxid, petroleum, creasote, and most essential oils interfere with 
the phosphorescence. 

Delicacy. — This test is extremely sensitive, having yielded un- 
mistakable evidence from -gV gr. of phosphorus diffused in 3 oz. 
of fluid (1 : 200,000). 

The Phosphin Test. — Having set up the usual hydrogen-gener- 
ating apparatus — that is, flask, pure zinc, and dilute sulphuric 
acid — the gas is delivered by a three-way tube, having a side jet, 




Fig. 57. — The bands represent the green lines of the spectrum of burning phosphin. They are between 
the lines D and E of the solar spectrum (Boisbaudran). 

to a wash flask containing the suspected organic mixture, and 
gently heated. The nascent hydrogen acting on the phosphorus, 
phosphids, or its lower oxids in the mixture will form phosphin 
(PH 3 ), a gas which will escape from the heated flask by a tube 
drawn out to a jet and having a platinum tip. When lighted, the 
phosphin, if not too concentrated, will burn with a characteristic 
green color. It may be contrasted with the flame from the side 
jet, which should be the pale-blue hue of pure hydrogen. If this 
side jet is greenish, there must have been some phosphorus in 
the zinc of the generator. To make sure, the greenish flame 
should be studied with the spectroscope. If due to phosphorus, 
it will show one orange band between C and D, and several green 
bands (Fig. 57). Both the color of the flame and its spectrum 
are best developed if the temperature of the flame is not allowed 
to rise too high. This may be accomplished conveniently by 
allowing the flame to impinge against the bottom of a porcelain 
dish filled with cold water, or by wrapping the burner with a 
small strip of cloth saturated with cold water. 



i86 



NON-METALS 



Phosphorescence in Hydrogen. — This test for free phosphorus 
only is best performed with the apparatus of Mukerji (Fig. 58), 
made from a three-necked Woulfe's bottle of i-liter capacity, by 
inserting through close-fitting stoppers a long safety funnel tube 
(a) in one side-neck, and a short jet tube (c) in the other. Through 
a loose-fitting one at the middle neck rises a tube 11 in. long 
and J in. in diameter, which is closed above by a cork (b). From 
zinc and dilute sulphuric acid in the bottle hydrogen is evolved. 
Observed in the dark, the gas at the jet should emit no glow, even 
if commercial chemicals are used. When the chemical action has 
heated the bottle, the suspected material is introduced through the 
middle tube or through either neck, quickly closing again with 
the stopper. 

Free phosphorus is vaporized and glows in a sheaf of light at 
the jet. If the middle cork is removed, 
the light sinks down through the jet into 
the bottle, and the glow appears at the 
outer opening of the middle tube. 

Replacing the cork causes the glow 
to reappear at the jet. If a quantitative 
estimate is desired, a proper delivery tube 
may be substituted for the jet and the gas 
passed into silver nitrate. 

Special Advantages. — The apparatus 
is simple, and as no lamp is required for 
distillation, complete darkness is possi- 
ble. The amount of air entering by the 
jet tube is so small in comparison with 
the quantity of hydrogen continuously 
evolved that the mixture is never explo- 
sive. Before taking apart, the apparatus 
should be filled with water by the funnel 
tube. 

While this test gives a glow with free 
phosphorus only, and not with any of 
its compounds, the phosphin test gives a 
green flame on ignition of the gas when 
the materials contain phosphorus, phos- 
phids, phosphites, or hypophosphites in- 
differently. Free phosphorus does not 
unite with free hydrogen, and the gas here is not phosphin. 

Interferences. — Turpentine or ether will prevent the glow in 
this test. It can be performed in the presence of organic matter, 
alcohol, iodin, hydrogen sulphid, and many other substances that 
prevent the glow in Mitscherlich's test. 




Fig. 58. — Phosphorescence in hy 
drogen. 



PHOSPHORUS 187 

Delicacy. — Mukerji found the test as sensitive as that of Mitsch- 
erlich, getting appreciable effects from 1 : 200,000. 

Quantitative Estimation. — Sonnenschein's method for free 
phosphorus is first to estimate the phosphoric acid by diluting the 
suspected mixture, filtering a measured fraction, and precipitating 
with magnesian mixture, estimating as ammoniomagnesian phos- 
phate. Another portion treated on a water-bath with potassium 
chlorate and hydrochloric acid will have its free phosphorus 
oxidized to phosphoric acid. This, being estimated, will show 
an excess over the first portion. The excess is then to be calcu- 
lated as free phosphorus. 

Period for Postmortem Recognition. — Tested by Mitsch- 
erlich's method, characteristic phosphorescence has been obtained 
in putrid organs two months after death and burial. There has 
been failure, however, to detect the poison even a few days after 
death, because of the conversion of the phosphorus into ammo- 
niomagnesian phosphate or some other salt of no medicolegal 
interest. 

Phosphorus and hydrogen form three compounds, to all 
of which the name phosphoretted hydrogen is applied, namely: 
PH 3 , at ordinary temperatures a gas; PH 2 , a liquid; and P 2 H, 
a solid. 

Phosphin (PH 3 ). — Phosphorus terhydrid or gaseous phosphor- 
etted hydrogen when inhaled is a very poisonous gas, reducing 
the oxyhemoglobin of the blood. It can be made by boiling 
phosphorus with strong potash or soda lye, or by generating 
hydrogen in the presence of the lower oxids of phosphorus. 

3KOH + 4 P -f 3H 2 = 3 KH 2 P0 2 + PH 3 . 

Potassium hypophosphite. 

It is colorless, sparingly soluble, and, as ordinarily made, it 
contains another hydrid, PH 2 , which causes it to inflame spon- 
taneously on contact with the air. When evolved with hydrogen 
it burns with a greenish- flame, but if dry and insufficiently sup- 
plied with air, the flame is white. When passed through a solu- 
tion of silver nitrate, the silver is deposited as metal, leaving nitric 
and phosphoric acids in solution; by adding excess of molybdic 
acid the phosphoric acid can be detected. 

Phosphorus and Oxygen.— When phosphorus burns in air 
it forms phosphorus pentoxid, P 2 5 . When the oxidation is incom- 
plete three other compounds are made, thus: P 2 4 , the tetroxid; 
P 2 3 , the trioxid; P 4 0, the suboxid. 

Phosphorus pentoxid, or phosphoric anhydrid, is a white 
compound remarkable for its power of combining with water. 



l88 NON-METALS 

When its combining powers with water are fully satisfied, phos- 
phoric acid results: 

P 2 5 + 3H 2 = 2 H 3 P0 4 

Phosphoric acid. 

When the trioxid unites with water it forms phosphorous acid:: 
P 2 3 + 3 H 2 = 2H3PO3 

Phosphorous acid. 

Phosphoric acid (H 3 P0 4 ), or orthophosphoric acid, is the- 

common acid used in medicine under the name acidum phos- 
phoricum. The dilute official acid is made by mixing the strong 
with a sufficient quantity of water to make a 10 per cent. acid. 
The strong acid can be made by dissolving the pentoxid in water, or 
by the direct oxidation of phosphorus with strong nitric acid. The 
phosphates of the soils and of the animal and vegetable tissues are 
its salts. 

Properties. — It is a non-corrosive, viscous liquid, colorless, 
odorless, with a pleasantly sour taste. It crystallizes with diffi- 
culty, when heated loses water, and at low redness volatilizes. It. 
is a tribasic acid, forming three classes of salts, with a univalent 
metal. The point of transition as shown by litmus from acid to 
neutral reactions is not sharp when sodium hydroxid is added to 
dilute phosphoric acid. The alkaline indication appears before 
two hydrogen atoms are replaced. The alkalinity gradually 
increases until all the hydrogen has been replaced by the metal, 
and the normal salt produced is decidedly basic in reaction. The 
three salts possible with sodium are: 

Na 3 P0 4 , normal, tertiary, or trisodium phosphate. It is an 
unstable and basic compound, alkaline in reaction. 

Na 2 HP0 4 , secondary or disodium phosphate. Though retain- 
ing some acid hydrogen, yet this phosphate is feebly alkaline. It 
exists in the blood and is permanent. 

NaH 2 P0 4 , acid, primary, or monosodium phosphate. It. gives, 
the acid reaction to urine. 

The peculiar reactions to litmus shown by these salts are due. 
to the difference in dissociation of the three hydrogen atoms. Per- 
fect breaking down of H 3 P0 4 into H', H", H' (PO- 4 )'" does not 
occur all at once in aqueous solution, nor readily at any time., 
While it does come eventually, the hydrogen ions> like those of 
other weak acids, are not completely dissociated in the beginning.. 
The first ions of H 3 P0 4 dissociate easily as H* and (H 2 P0 4 )'. 
When the base sodium hydroxid is added to it the H* is removed,, 
the second dissociation sets in, and the (H 2 P0 4 )' breaks down into. 
H* and (HPOJ". Further dilution or the action of more baser 



PHOSPHORUS 189 

separates the anion (HP0 4 )" into H* and (P0 4 )'". This complete 
electrolytic dissociation is so slight that the water comes into play 
as it does with the other weak acids, and hydrolytic dissociation 
occurs, causing a different group of ions. In watery solution the 
interaction causes the normal sodium phosphate to break down in 
the manner indicated by the following equation: 

Na 3 P0 4 + H 2 = Na«, Na% (HP0 4 )" + Na*,(HO)'. 

The hydroxidion (HO)' thus liberated as a result of the two dis- 
sociations is the cause of the alkaline reaction of Na 3 P0 4 . The 
secondary phosphate, Na 2 HP0 4 , in water undergoes some degree 
of hydrolysis, and therefore gives a feebly alkaline reaction. With 
monad and dyad bases phosphoric acid forms double salts, such 
as ammoniomagnesian phosphate, NH 4 MgP0 4 , found in stale 
urine, and potassiobarium phosphate, KBaP0 4 . 

Tests for Phosphoric Acid and Phosphates. — (1) The phosphates 
are precipitated as white ammoniomagnesian phosphate by mag- 
nesia mixture (containing magnesium sulphate, ammonium chlo- 
rid, and ammonium hydroxid): 

H 3 P0 4 +MgS0 4 + 3NH 4 OH = MgNH 4 P0 4 +(NH 4 ) 2 S0 4 + 3 H 2 0. 

Ammoniomagnesian Ammonium 

phosphate. sulphate. 

(2) Ammonium silver nitrate throws down a yellow precipi- 
tate of silver phosphate which is soluble in ammonia and nitric 
acid: 

H 3 P0 4 + 3 (AgN0 3 , NH 3 ) = Ag 3 P0 4 + 3 NH 4 N0 3 . 

(3) An excess of solution of ammonium molybdate in dilute 
nitric acid will precipitate the phosphoric acid if heated gently: 
the yellow precipitate is phosphomolybdate of ammonium. 

(NH 4 ) 3 P0 4 , ioMoO s , 2H 2 0, 

which dissolves easily in ammonia-water. This test, unlike (1) 
and (2), can be used in acid solution and is the most delicate. 

Incompatibles oj Acidum Phosphoricum. — It is incompatible 
with silver nitrate, ferric chlorid, lead acetate, and solutions of 
soluble iron phosphate or pyrophosphate. Dose 3 to 7 Tit (0.20- 
0.66 gm.). 

Metaphosphoric Acid (HP0 3 ). — Properties. — A transparent 
glassy mass, known as glacial phosphoric acid. It is a monobasic 
acid. 

Preparation. — Metaphosphoric acid is formed when ortho- 



190 NON-METALS 

phosphoric acid is heated higher than is necessary to produce 
pyrophosphoric. 

Upon the addition of water to this glacial acid, a solution is 
obtained, which, upon boiling, is converted into the tribasic phos- 
phoric acid, H 3 P0 4 . 

It is detected by the precipitation of its barium salt as a white 
solid. A mixture of albumin with acetic acid gives a white pre- 
cipitate to its solution. 

Pyrophosphoric Acid (H 4 P 2 7 ). — Properties. — It can be ob- 
tained as crystals by evaporation in vacuo. It is tetrabasic. 

Preparation. — Pyrophosphoric acid is prepared (1) by heating 
the tribasic phosphoric acid, H 3 P0 4 , to 213 ° C. (415. 4 F.). 
Thus: 

2 H 3 P0 4 = H 2 + H 4 P 2 7 

Water. Pyrophosphoric acid. 

(2) By the action of hydrogen sulphid, H 2 S, on pyrophosphate 
of silver, Ag 4 P 2 7 . Thus: 

Ag 4 P 2 7 + 2H 2 S = 2 Ag 2 S + H 4 P 2 7 

Sulphid of silver. Pyrophosphoric acid. 

It is identified by the white precipitate falling upon the addition 
of silver nitrate, but no precipitate is caused by albumin and acetic 
acid. 

The three acids above described may be prepared by acting 
upon phosphorus pentoxid, P 2 5 , with different proportions of 
water, as follows: 

P 2 5 -]- H 2 = 2HP0 3 , Metaphosphoric acid, monobasic. 
P 2 5 -j- 2 H 2 = H 4 P 2 7 , Pyrophosphoric acid, tetrabasic. 
P 2 5 -|- 3H 2 = 2H 3 P0 4 , Orthophosphoric acid, tribasic. 

By heating to 300 ° C. (572 ° F.) the tribasic phosphoric acid,. 
2H 3 P0 4 , and thus driving off a molecule of water, we can obtain the 
pyrophosphoric acid, H 4 P 2 7 , and by the action of heat to 400 ° C. 
(752 ° F.) upon this, with the loss of another molecule of water, we 
obtain the metaphosphoric acid, 2HP0 3 . 

Phosphorous Acid (H 3 PO s ). — Properties. — It forms deliques- 
cent crystals which readily decompose; throws down gold, silver, 
and platinum from their solutions. As a colorless acid liquid it is 
dibasic, only 2 H atoms will ionize, as in the formula H*, H*, 
(HP0 3 )". It is a strong deoxidizer, uniting with oxygen to form 
phosphoric acid. Its salts are called phosphites. 

Preparation. — Phosphorous acid is formed by acting upon the 
trichlorid of phosphorus, PC1 3 , with water, H 2 0. Thus: 

PCI3 + 3 H 2 = 3HCI + H 3 P0 3 . 



CARBONIC ACID 191 

Hypophosphorous Acid (H 3 P0 2 ).— Properties.— An acid syr- 
upy fluid and powerful deoxidizer; precipitates gold and silver from 
their solutions. All the hypophosphites are soluble in water. It 
is a white crystalline substance, having but one atom of replaceable 
hydrogen. This may be expressed by writing it as H*,(P0 2 H 2 ) / . 
The other hydrogen atoms have no acid quality and will not ionize. 

Preparation. — This acid is prepared by acting upon barium 
hypophosphite, Ba(H 2 P0 2 ) 2 , with sulphuric acid, H 2 S0 4 . Thus: 

Ba(H 2 P0 2 ) 2 + H 2 S0 4 = BaS0 4 + 2 H 3 P0 2 . 

Acidiun hypophosphorosum dilutum contains 10 per cent. 
H 3 P0 2 . Dose 10 to 60 TTL (0.66-4.00 gm.). 

Phosphorus with chlorin forms two compounds, viz.: PCI3, 
phosphorus trichlorid; PC1 5 , phosphorus pentachlorid. 

Phosphorus trichlorid, PC1 3 , is a colorless, volatile, strongly 
fuming liquid, and is formed by passing chlorin gas over phos- 
phorus. It gradually decomposes into hydrochloric acid and 
phosphorous acid. It may also be formed by the combustion of 
phosphorus in chlorin gas. 

Phosphorus pentachlorid, PC1 5 , is a solid crystalline substance, 
and decomposes by excess of water into hydrochloric acid, HC1, 
and tribasic phosphoric acid, H 3 P0 4 . It is prepared by passing 
excess of chlorin through the phosphorus trichlorid. Should water 
be present only in limited quantity, a liquid called phosphoric 
oxychlorid, PCl s O, is formed. Thus: 

PC1 5 + H 2 = 2HCI + PCl s O. 

Phosphorus forms with iodin PI 3 and PI 5 , with bromin PBr 3 
and PBr 5 , and it burns spontaneously in those substances when 
they are in the gaseous state. By the action of sulphuretted hy- 
drogen, H 2 S, upon phosphorus pentachlorid, PC1 5 , a substance 
termed phosphoric sulphochlorid, PSC1 3 , is obtained. 

Phosphorus forms several compounds with sulphur, two of 
them, P 2 S 3 and P 2 S 5 , corresponding in composition with the oxids 
P 2 3 and P 2 O . 

CARBONIC ACID 

Formula, H 2 C0 3 . Atomic weight, 62. 

In another section the element carbon and its two oxygen 
compounds, carbon monoxid and carbon dioxid, have been fully* 
discussed. Mention was made of the fact that when dissolved in 
water carbon dioxid became carbonic acid, and in this form was 
widely known in the aerated liquid commonly called soda water. 
If the freshly drawn aerated water be tested before much gas 



192 NON-METALS 

escapes, it will be found to give the usual red reaction with litmus. 
The gas C0 2 , like S0 2 , is an anhydrid, converted to an acid by 
water; H 2 C0 3 , resembling in this respect H 2 S0 3 , sulphurous 
acid. Like that acid, H 2 CO s readily decomposes into H 2 and 
the anhydrid C0 2 . Carbonic acid is a weak dibasic acid. It 
resembles H 2 S0 3 and other dibasic acids — in that it breaks up 
into two different anions, first into the univalent (HC0 3 )', and next 
into the divalent carbanion (CO s )". Being a very weak acid, dis- 
sociation is very slight indeed, whether it be at the first stage, 
H 2 CO s = H*, (HCO s )', or at the less appreciable second (HCO s )' 
= H # , (C0 3 ) r/ . The dominant anion appears to be (HC0 3 /, 
the solution tending to form this group by preference. 

The carbonates are very abundant in nature, among them 
being limestone, marble, and chalk; and they are in general quite 
insoluble in water. All carbonates, except those of the alkali 
metals, are of difficult solubility. Both the normal sodium car- 
bonate, Na 2 C0 3 , and the acid salt, NaHCO s , have an alkaline 
reaction. As this indicates the presence of hydroxidion (HO)' it 
appears that the soluble carbonates are hydrolyzed — that is, the 
ions are changed by interacting with the water. A part, at least, 
of this hydrolysis may be represented by the following equation: 

Na 2 C0 3 + H 2 = Na-, (HO)' + Na«, (HCO s )'. 

Obeying its tendency, the carbanion (C0 3 )" breaks up the H 2 
to form the ions (HC0 3 )' and (HO)'. A small amount of hydrox- 
idion is sufficient to give an alkaline reaction to solutions of 
NaHC0 3 . The reactions indicated above characterize all soluble 
carbonates. 

DERIVATIVES OF CARBONIC ACID 

Beside the numerous class of carbonates in which the hydro- 
gen only is replaced by metals, there are important compounds 
which may be regarded as derived from carbonic acid by replace- 
ment of its hydroxyls in CO(OH) 2 , with chlorin and with amido- 
gen, NH 2 . The two most important are carbonyl chlorid, COCl 2 , 
and carbonyl diamid or urea, CO(NH 2 ) 2 . 

Carbonyl Chlorid (COCl 2 ) {Carbon Oxychlorid).— This com- 
pound is known as phosgene gas because it is generated by the 
action of direct sunlight on a mixture of equal proportions of 
carbon monoxid, CO (carbonyl), and chlorin, CO + Cl 2 = COCl 2 . 
The same reaction occurs by catalysis when the mixed gases are 
passed over charcoal (p. 386). 

Properties. — Carbonyl chlorid is a gas without color, but with 
a stifling odor. When inhaled it is a suffocative poison (p. 388). 



DERIVATIVES OF CARBONIC ACID 1 93 

In the presence of water it is decomposed with the formation of 
carbonic acid and hydrochloric acid: 

COCl 2 + 2H 2 = HXO3 + 2HCI. 

Carbonic Acid Diamid. — The most significant reaction of 
carbonyl chlorid is one by which we may infer the constitution of 
urea. When ammonia is permitted to act on COCl 2 there is 
decomposition of the carbonyl chlorid with formation of ammo- 
nium chlorid and a compound containing carbonyl and two parts 
of the group NH 2 , characteristic of amids, thus: 

COCl 2 + 4NH3 = CO(NH 2 ) 2 + 2NH 4 C1 

Ammonia. Carbonyl diamid. Ammonium chlorid. 

By extracting with alcohol the carbonic acid diamid is separated 
from the insoluble ammonium chlorid, and on evaporation is left 
as colorless crystals. These crystals are neutral in reaction, 
without odor, but having a bitter taste. In solution they have no 
electroconductivity, hence are non-electrolytes. 

This substance is found abundantly in the body and urine of 
carnivora, and is known commonly as urea. 

Carbon Disulphid (CS 2 ). — The relationship of carbon dioxid, 

ATT 

C0 2 , to carbonic acid, CO< nT j, has already been referred to. 

CTT 

There is a trithiocarbonic acid, CS<~ TT , in which all the oxygen 

has been replaced by sulphur, and it has a corresponding disulphid, 
CS 2 . This is prepared by passing vapor of sulphur over heated 
charcoal. It is a highly refractive, colorless, volatile, inflammable 
liquid, neutral in reaction, with a peculiar odor. It boils at 46 ° 
C. (115 F.). It is not miscible with water, but freely dissolves in 
alcohol, ether, and chloroform. It is a valuable solvent for iodin, 
phosphorus, sulphur, etc. 

Toxicology. — Owing to its employment in the manufacture of 
vulcanized rubber, cases of chronic poisoning from inhaling the 
vapor are not rare. Workmen exposed to it in imperfectly ven- 
tilated factories experience at first a form of excited intoxication 
characterized by vivacious talking, singing, immoderate laughter, 
causeless weeping, and delirium. They also complain of head- 
ache, vertigo, and muscular cramps. If the person does not 
change his occupation the second stage appears, in which there 
is headache, drowsiness, melancholy, weakness, and loss of feeling 
in the extremities, ending in paralysis. 
13 



194 NON-METALS 

THE CYANOGEN GROUP 

One of the simplest compounds of carbon is the gas cyanogen, 
(CN) 2 , formed when carbon and nitrogen unite in the heat of the 
electric arc. All of its derivatives contain the group CN, just as 
the chlorids, hypochlorites, etc., contain CI. 

Many of its compounds have properties resembling those of 
the chlorin family, though they contain this univalent group of 
atoms, CN, in place of the single atom, CI. Sometimes it is writ- 
ten Cy, to indicate that the group CN acts like a single element, 
just as NH 4 behaves like the single atom of an alkaline metal. 

The term radical or radicle is applied to a group playing the 
part of an atom. The relation between HCN and HC1 is shown 
by the following examples, in which CN acts like the electro- 
negative element: 

HC1, KC1, AgCl, HgCl 2 , HOC1. 
HCN, KCN, AgCN, Hg(CN) 2 , HOCN. 

Preparation. — Cyanogen is prepared by heating -mercuric 
cyanid to a red heat in a hard glass reduction tube, connected by 
a perforated cork and delivery tube with a trough of mercury: 

Hg(CN) 2 = Hg+C 2 N 2 . 

Mercury is deposited upon the cool portions of the tube. 

Properties. — The free gas is colorless, condensing to a liquid 
under a pressure of four atmospheres; it has a characteristic odor, 
is an active poison, and burns with a purple flame into carbon 
dioxid and nitrogen. It is soluble in water and alcohol, but its 
aqueous solution is unstable, depositing a brownish precipitate. 

Hydrocyanic Acid (HCN) (Prussic Acid).— This compound 
is sometimes called absolute, pure, or anhydrous, to distinguish it 
from the official form, acidum hydrocyanicum dilutum, which con- 
tains not less than 2 per cent, of the anhydrous, according to the 
pharmacopeias of U. S., Great Britain, Prussia, Switzerland, and 
Norway. The French official article contains 10 per cent., which 
is the average strength of Scheele's acid. They are all so unstable 
that in any but fresh specimens the strength is uncertain. The 
following parts of plants can be made to yield HCN by appropriate 
treatment: wild-cherry bark; flowers and leaves of the laurel and 
the peach; kernels of peach, plum, apple, cherry, and apricot; the 
bark, leaves, flowers, and fruit of the wild service tree (Prunus 
padus); the leaves and flowers of the shrubby spiraea. These and 
other plants contain amygdalin, a glucosid found abundantly in 



HCN + 


2C 6 H 12 6 


+ 


C 7 H 6 


vdrocyanic 


Glucose. 




Oil of bitter 


acid. 






almonds. 



THE CYANOGEN GROUP 195 

Amygdala amara, the bitter almond. When the vegetable tissue 
is bruised or chewed, amygdalin is brought into contact with emul- 
sin, a ferment which in the presence of water breaks up the amyg- 
dalin into hydrocyanic acid and other compounds: 

C 22 H 27 XO u + 2 H 2 

Amygdalin. 



According to Liebig and Wohler, 17 gm. of amygdalin yield 
1 of hydrocyanic acid and 8 of oil of bitter almonds. 

Oleum amygdalce amarce contains 2 to 4 per cent, of hydro- 
cyanic acid. 

Preparation. — Prussic acid can be prepared by the action of 
hydrochloric acid on silver cyanid: 

AgCN + HC1 = AgCl + HCX 

Silver cyanid. Hydrocyanic acid. 

The silver chlorid is precipitated, and the acid collected in the 
filtrate. Usually it is made by distilling potassium ferrocyanid or 
cyanid with sulphuric acid, just as hydrochloric acid is made by 
the action of sulphuric acid on sodium chlorid. 

KCN + H 2 S0 4 = HCN + KHS0 4 . 

Potassium cyanid. 

The dilute acid (2 per cent.) is the only form used in medicine. 
Its dose is 2 to 5 TIT (°- I2- °-3S g m -)> repeated at short intervals. 
It is incompatible with salts of copper, iron, and silver. When it 
turns brown it is unfit for use. 

Properties. — Absolute or anhydrous prussic acid is a colorless 
volatile liquid with an odor like oil of bitter almonds. It reddens 
litmus feebly, dissolves freely in water, but the solution rapidly 
separates a brown substance and changes to ammonium formate: 

HXC + 2H 2 = NH 4 H.C0 2 

Ammonium formate. 

It is a poison so powerful and unstable that it is not kept in 
the drug-stores in its anhydrous form. 

Toxicology. — The least quantity that has destroyed life is 
\ fl. dr. of the official dilute acid or to gr. of the anhydrous acid. 
The inhalation of the vapor has produced death. Recovery has 
occurred after taking 1 fl. dr. of Scheele's acid, and in another case 
after 2 fl. dr. of the official acid, which, if not deteriorated, should 
have been equal to 2.4 gr. of anhydrous acid. 



196 NON-METALS 

Symptoms. — Prussic acid is a retarding catalyzer — i. e., by its 
presence prevents oxidation and other vital processes important 
to the life of the organism. It depresses the nutrition of proto- 
plasms in plants and animals. Applied externally, care must be 
exercised lest the poison enter by open cuts. The anhydrous 
acid has been used as a local application for allaying oversensi- 
tive conditions of the cutaneous nerves. Instant death may follow 
large doses by the mouth or the inhalation of vapor of the strong 
acid. 

If death is not instantaneous, then in a few seconds there will 
be giddiness, relaxed muscles, causing a fall to the earth, convul- 
sions, stertorous breathing, slowing of the pulse, closed jaws, clammy 
skin, odor of bruised peach-kernels on the breath, dilated pupils, 
asphyxia, stupor, ending in coma. In some cases the resemblance 
to apoplexy is so marked as to cause mistake in diagnosis. Insensi- 
bility is not always immediate, though death is usually preceded 
by convulsions and coma. Death is due to arrested respiration. 

Fatal Period. — In most cases ten minutes elapse before death. 
Consciousness may be lost in a few seconds, the suicide falling 
dead in two minutes. 

It is possible that life may be prolonged for three hours and a 
half, but in most cases if the patient live an hour he will recover. 

Treatment. — If strong prussic acid has been taken there is rarely 
time for treatment. After potassium cyanid or the dilute acid 
there may be opportunity for the following procedure: 

Give prompt emetics, such as mustard and water, aided by 
tickling the throat. 

By the flexible tube, siphon out the stomach with Kobert's 
antidote — dilute solution of hydrogen peroxid, which slowly con- 
verts HCN into relatively harmless oxamid: 

2HCN + H 2 2 = C 2 2 N 2 H 4 

Hydrogen peroxid. Oxamid. 

If potassium cyanid was the form of poison, add vinegar to the 
hydrogen peroxid. Should death be delayed there may be time 
for the antidote of potassium carbonate, gr. xx, dissolved in water, 
f3J, followed with a mixture of ferrous sulphate, gr. x, and mag- 
nesia, gr. xxx, in water, f^j. The poisonous anion cyanidion, 
(CN)', is changed to ferrocyanidion, Fe(CN) 6 "", which is not 
poisonous in the presence of an alkali. 

In mining and photographic laboratories the materials for this 
antidote should be kept made up in packages and the stomach 
tube be always at hand for use without delay. 

Cold affusions over the face and chest and inhalations of 



THE CYANOGEN GROUP 197 

ammonia may be assisted by brandy subcutaneously administered, 
frictions to the extremities, and artificial respiration. 

Atropin, -^0 gr., may be given hypodermically as a stimulant 
to heart and respiration. 

Postmortem Appearances. — -The odor of bruised peach-kernels 
may be noticed in the room or on the body. There are no char- 
acteristic lesions, but most frequently there is engorgement of the 
venous system, the arteries being empty. The postmortem stains 
are bright pink, due to the cyanohematin of the blood and to the 
fact that the tissues cannot take up the oxygen of the blood, 
leaving it red even in the veins. 

Tests. — Silver nitrate produces a white precipitate, soluble in 
boiling, strong, nitric acid: 

HCN + AgN0 3 = HN0 3 + AgCN. 

This white silver cyanid is distinguished from the chlorid by 
being only sparingly soluble in ammonia, by its not turning dark 
on exposure to light, and by giving off cyanogen gas when heated, 
the cyanogen burning with a purple flame. Under a lens the 
cyanid may appear as prismatic needles, while the chlorid is 
amorphous. 

The most delicate test is this one used on HCN in the state of 
vapor. The suspected matters are put in a beaker which is im- 
mersed in a basin of warm water. The mouth of the jar is cov- 
ered with a watch crystal, which has on its concave under side 
a drop of weak solution of silver nitrate. Hydrocyanic-acid vapor 
causes a white film over the drop, which, if slowly formed, will be 
seen by the microscope to consist of delicate crystalline prisms. 
If putrefaction has set in, the test cannot be used, as the black 
silver sulphid masks the white cyanid. 

Prussian-blue Test. — On the addition of potassium hydrate, 
followed by fresh ferrous sulphate and ferric sulphate, a greenish- 
blue precipitate forms, which is turned to a clear Prussian blue by 
the addition of hydrochloric acid. 

18HCN + 18KHO + 5FeS0 4 + Fe 2 (S0 4 ) 3 + H 2 S0 4 = 

Ferrous sulphate. Ferric sulphate. 

9K 2 S0 4 + Fe 4 (Fe(CN) 6 ) 3 + i8H 2 + H 2 . 

Ferric ferrocyanid. 

Ammonium-sulphid test may be used upon fluids in a test-tube, 
but gives best results with the vapor of HCN, even after putre- 
faction has begun. The stomach contents or other suspected 
matter are put in a jar which is immersed in warm water, and the 
mouth closed with a glass plate carrying a drop of ammonium 



198 NON-METALS 

sulphid. A white ammonium sulphocyanid soon appears in this 
drop on the under side. This drop is then evaporated almost to 
dryness and touched with a drop of ferric chlorid, when it de- 
velops a blood-red color, which is discharged after treating with 
mercuric chlorid: 

HCN + NH 4 HS = 2H + NH 4 SCN 

Ammonium sulphid. Ammonium sulphocyanate. 

3 NH 4 SCN + FeCl 3 = 3NH 4 C1 + Fe(SCN) 3 

Ferric chlorid. Ammonium chlorid. Iron sulphocyanate. 

Detection. — If death has been recent, the odor of peach- 
kernels may be perceived. The stomach, its contents, and other 
tissues should be distilled at a low temperature without acidu- 
lating, as acids may form a cyanid by decomposing the normal 
potassium sulphocyanate of the saliva. 

Instead of acidulating the suspected matter before distillation, 
J r acquemiri 's process is to mix it with a concentrated solution of 
sodium bicarbonate, which evolves C0 2 , a gas that promotes the 
escape of HCN and liberates HCN if potassium cyanid be pres- 
ent, but does not decompose potassium sulphocyanate nor potas- 
sium ferrocyanid nor other non-poisonous cyanids. 

Any of the above tests may be applied to the vapor, or the 
distillate in the receiver may be treated with potassium hydrate 
and tested for potassium cyanid or silver nitrate. The resulting 
silver cyanid is washed, dried, and weighed. For every 100 parts 
of AgCN we may calculate 20.15 parts of anhydrous HCN. 

Potassium Cyanid (KCN).— This compound figures quite 
frequently as a poison, because of its extensive use in the arts of 
photography and electroplating, and in the extraction of gold 
from its ores by the cyanid process. 

Properties. — It occurs in opaque, white, strongly alkaline, del- 
iquescent masses, which have the taste of bitter almonds, and in 
contact with the air are decomposed by C0 2 with the slow forma- 
tion of hydrocyanic acid, recognized by the odor. 

As hydrocyanic acid is a weak acid, its salt is hydrolyzed by 
the water, forming hydroxidion, which is alkaline, and hydrogen 
cyanid, which is scarcely dissociable, and hence is given off as 
molecules with the characteristic odor. This is in accordance 
with the equation: 

KCN + H 2 = K',(OH)' + HCN. 

It is soluble in two parts of water, and is sometimes used in 
medicine as a sedative in doses of -%-$ to -§■ gr. Its incompatibles are 



THE CYANOGEN GROU 199 

acids; iodin; salts of lead, mercury, and silver; chlorates; nitrates; 
permanganates; alkaloids; chloral hydrate. 

Toxicology. — Symptoms. — Its physiologic effects are like those 
of hydrocyanic acid. The convulsive and narcotic symptoms are 
often preceded by those of gastric irritation, such as pain and 
vomiting. The onset of symptoms is slower than by the acid, 
thus giving more time for treatment. 

The treatment is practically the same as that given for the acid, 
p. 196. 

Postmortem Appearances. — There is usually marked congestion 
of the stomach, due to the strongly alkaline salt. A bright red 
hue is Observable in the throat, esophagus, and stomach, due to 
the formation of cyanohematin by the penetration of the salt to 
the blood in the tissues. 

Tests. — When treated with dilute acids potassium cyanid is 
quickly decomposed, and to the vapor the various tests for hydro- 
cyanic acid may be applied. Silver nitrate reacts directly, precipi- 
tating white silver cyanid- and the potassium is detected by plat- 
inum chlorids. In making the Prussian-blue test the potassium 
hydrate must be omitted. 

Other Cyanids. — The soluble metallic cyanids and methyl 
cyanid are all poisonous, as they dissociate the active anion (CN)'. 
If the cation be poisonous also, as in mercury cyanid, Hg # , (CN)/, 
the symptoms will be those of an irritant mercurial salt in addition 
to those of potassium cyanid. 

Poisonous, also, are the chlorid and iodid of cyanogen. In 
neutral or alkaline menstrua the double cyanids, not having as 
anion, cyanidion, (CN), but ferrocyanidion, Fe(CN) 6 "", are con- 
sidered relatively harmless. It must not be forgotten that in the 
presence of acids the iron of Fe(CN) 6 //// may be taken up, and the 
(CN) group be freed to do its deadly work. 

In cyanic acid and its salts, the cyanates, the anion is not (CN)', 
but (OCN)', which is not poisonous. The sulphocyanates are not 
seriously injurious, as they have the anion (SCN)'. 

Cyanic acid, H . OCN, is a strongly acid, unstable liquid, 
forming cyanates. In water it quickly changes to acid ammonium 
carbonate: 

HOCN + 2 H 2 = (NHJHCO3. 

Potassium cyanate, KOCN, is formed when potassium cyanid 
slowly oxidizes in the air, though it is usually prepared by heating 
KCN with a reducible metallic oxid and then extracting the prod- 
uct with dilute alcohol: 

KCN + PbO - KOCN + Pb. 



200 NON-METALS 

It is a colorless crystal and readily soluble. When its solution is 
mixed with ammonium sulphate, ammonium cyanate is formed: 

2KCNO + (NH 4 ) 2 S0 4 = 2 (NH 4 ).CNO + K 2 S,0 4 - 

Ammonium cyanate. 

If the resulting solution be evaporated on a water-bath, the 
ammonium cyanate is transformed into urea. It was in this way 
that Wohler first produced urea by artificial synthesis. There is 
no addition or subtraction of atoms, as the two substances have 
the same molecular formula. The change is termed intramolecular 
and may be expressed by the constitutional formulas given below: 

NH 4 .O.CN = CO(NH 2 ) 2 

Ammonium cyanate. Urea or carbonyl diamid. 

It is believed that there is a migration of atoms to differently 
arranged groups. The two bodies are said to be isomeric — i. e., 
although they have the same composition their properties differ 
because of a difference of arrangement in the atoms. ^ 

OXALIC ACID (Acid of Sugar) 

Formula, C 2 H 2 4 + 2H 2 0. Molecular weight, 125.7. 

Oxalic acid and its salts are widely present in nature, being found 
in various plants, such as rhubarb (used for pies), nightshade, dock, 
sorrel (oxalis) (used for greens), and in animals also, occurring not 
infrequently as a constituent of the human urine. In the latter 
it is incidental to the gouty condition and some forms of dyspepsia, 
occurring as calcium oxalate in the form of a whitish deposit made 
up of microscopic crystals, octahedral or dumb-bell shaped, and 
insoluble in warm water and in acetic acid (p. 591). 

Preparation. — As a sodium salt it may be prepared by passing 
carbon dioxid over sodium heated carefully: 

Na 2 + 2C0 2 = Na 2 C 2 4 

Sodium. Carbon dioxid. Sodium oxalate. 

It can be prepared from sugar by oxidation with nitric acid, and, 
therefore, is sometimes known in the arts as acid of sugar. 

C 12 H 22 O u + 9 2 = 6C 2 H 2 4 + 5 H 2 0. 

Sugar. Oxalic acid. 

Its bleaching properties and solvent powers for metallic oxids 
make it useful to dyers and workers in leather, makers of straw 
hats and bonnets, and workers in marble and in brass. About 
the home it is used to remove ink-stains from linen. Druggists 
dispense it at a low price, and consequently the would-be suicide 



OXALIC ACID 20 1 

not infrequently resorts to it. Its resemblance to Epsom salts 
leads to accidental poisoning, but the very sour taste is likely to 
betray the homicide, who rarely resorts to it except when it can 
be masked by some other sour beverage. 

Properties. — The crystals of oxalic acid are colorless, four- 
sided, prismatic, not deliquescent, and so closely resemble in ap- 
pearance those of magnesium sulphate and zinc sulphate that it is 
often confounded with them. These crystals are very acid, soluble 
in about 10 parts of cold water and in 2\ of cold alcohol, but very 
sparingly in ether. Heated on porcelain or platinum, they sublime 
without residue. They contain two parts water of crystallization. 

It can be distinguished from the substances for which it is 
sometimes mistaken by the following ready tests, applicable in 
the household: 

Oxalic acid. Magnesium sulphate. Zinc sulphate. 

Taste Sour. Bitter, nauseous. Bitter, metallic. 

Reaction .... Very acid. Neutral. Slightly acid. 

Heated Sublimes. Fixed. Fixed. 

Sodium carbonate . No precipitate, No effervescence, but a No effervescence, but a 

but effervescence. white precipitate. white precipitate. 

Iron, ink .... Bleaches. No effect. No effect. 

As it is a dibasic acid it makes two salts with univalent metals. 
With potassium it forms KHC 2 4 and K 2 C 2 4 . 

Potassium Binoxalate (KHC 2 4 ,H 2 0) (Acid Oxalate).— 

This salt is usually dispensed by druggists to remove rust and 
ink-stains from linen, to bleach straw, and to polish metals, under 
the very deceptive name of "essential salts of lemon" and "salts 
of sorrel," and sometimes without even the "grim heraldry of 
death" usually blazoned on labels for poisonous substances. It 
is sometimes dispensed as a white powder, although it crystallizes 
in colorless rhombic prisms, having 1 part of water of crystallization. 
It has a decidedly acid reaction and sour taste, and is soluble in 40 
parts of water. It is likely to be mistaken for cream of tartar, 
which is also a sour white solid. Almost equal to oxalic acid in 
the violence of its poisonous action, its symptoms, postmortem 
appearance, antidotes, and detection are practically the same. 

The same may be said in lower degree to be true of the neutral 
potassium oxalate (K 2 C 2 4 ), which is white, crystalline, soluble 
in water and neutral in reaction. Not being used in the household 
it does not figure in toxicology, though when absorbed it is a violent 
neurotic poison. 

Toxicology. — Symptoms. — What is said of the toxic effects of 
oxalic acid is applicable also to potassium binoxalate. While the 
symptoms vary considerably in different cases, they can be con- 
veniently classified as, first, those due to the local erosive action on 



202 NON-METALS 

the mucous surfaces, and, second, those arising from the remote 
impression upon the nervous system — convulsive and narcotic. 
The symptoms produced by the local action of a large amount 
of a strong solution are very sour taste, thirst, pain, and burning 
in mouth, throat, and stomach, difficult swallowing, vomiting of 
black or bloody substances, collapse. Occasionally pain is absent. 
Sometimes death may occur without vomiting. 

"If," says Christison, "a person immediately after swallowing 
a solution of a crystalline salt which tasted purely and strongly 
acid is attacked with burning in the throat, then with burning in 
the stomach, vomiting, particularly of bloody matter, imperceptible 
pulse and excessive languor, and dies in half an hour, or still more 
in twenty, fifteen, or ten minutes, I do not know any fallacy which 
can interfere with the conclusion that oxalic acid was the cause 
of death. No parallel disease begins so abruptly and terminates 
so soon, and no other crystalline poison has the same effect." 

A case of oxalic-acid poisoning occurred in a boy aged fifteen 
years. Twelve minutes after the poison had been swallowed the 
patient was unconscious, the skin pallid and clammy, and his ex- 
tremities cold. The radial pulse could not be felt. The pupils 
were fairly dilated. The jaw was fixed in tetanic spasm, and froth 
exuded from between the teeth. One-tenth of a grain of apomor- 
phin was injected hypodermically; a stomach siphon-tube was 
introduced after the jaws had been forced apart, and i pint of 
warm water was placed in the stomach, but immediately expelled. 
Vomiting continued, and consciousness returned. The boy was 
given J oz. of powdered chalk, suspended in water, and this also 
was shortly ejected. Recovery proceeded under stimulation. The 
quantity of poison taken was upward of 2J drams. 

If, owing to the smallness of the dose, death is not prompt, 
absorption of the poison ensues, and then the remote or neurotic 
symptoms appear. These are headache, cramps, convulsions, 
delirium, and coma. If the patient survive, there may be numb- 
ness and tingling, with loss of voice, lasting for weeks. When a 
small dose has been taken in dilute solution, the symptoms have 
not come on for hours, and then the nervous phenomena are 
more prominent. 

Fatal Dose. — The least weight of the acid recorded as having 
fatal consequences is 1 dram (3.88 grams). Statistics show that 
the dose most likely to prove fatal is from | to 1 oz. Early vom- 
iting and a measure of relief are caused by excessive doses. More 
than 1 oz. (14.2 gm.), if retained, usually causes death, although 
recovery has occurred after a dose of 2 oz. 

If efficient antidotes are instantly given there may be recovery 
from much larger doses, although the majority of cases prove fatal. 



OXALIC ACID 203 

Fatal Period. — In 1 case death, supposed to be due to gas- 
tric hemorrhage, occurred without pain in three minutes. In other 
cases surviving the acute action on the alimentary tract death has 
occurred from coma after several days, 1 living until the twenty- 
third day. 

Treatment. — The chemical antidotes are finely divided chalk or 
calcined magnesia or its carbonate, suspended in a large quantity 
of water, and followed by free drafts of warm water to facilitate 
vomiting. As the toxic action is prompt, the antidote must be 
given at once. With a shovel or a kitchen knife the wall-plaster 
can be scraped off and used as an impure calcium carbonate. 

Oxalic acid is chemically neutralized by the alkalies as well as 
by the alkaline earths (lime and magnesia), but the alkaline 
oxalates, being soluble and poisonous, are inadmissible, while the 
oxalates of calcium and magnesium are insoluble and innocuous. 
Emetics may be necessary (such as 5 drops of a 2 per cent, solu- 
tion of apomorphin hydrochlorate). If the stomach-pump have a 
hard tube it is likely to injure the eroded lining of the gullet and 
stomach. 

Postmortem Appearances. — Colored stains upon the lips and 
face are absent, but the lips, tongue, throat, and gullet are usually 
white, and the lining membrane is loose, eroded in patches, and 
contracted into folds. Sometimes the stomach is black from ex- 
tensive venous engorgement and contains blood or a brownish, 
grumous material; sometimes the membrane is pale and smooth, 
or detached in shreds; sometimes red, with the black veins strongly 
marked and corrugated. While deep erosions are not uncommon, 
it is rare to have complete solution of the walls of the stomach, 
so as to cause the symptoms of perforation during life, Both 
peritonitis and pleuritis h^ve been found as complications, and 
perforations of the stomach also, but these last in some cases 
have been supposed to be due to changes after death. The kid- 
neys are congested and loaded with oxalates. 

Tests. — A solution of oxalic acid or of potassium binoxalate 
reddens litmus-paper. 

Calcium Test. — Either of them yields, with excess of calcium 
hydroxid, acetate, or sulphate, a white precipitate of calcium 
oxalate, insoluble in ammonia or acetic acid, but soluble in strong 
hydrochloric or nitric acid. 

Silver Nitrate Test. — Either of them gives with silver nitrate 
a copious white precipitate of silver oxalate, soluble in ammonia 
and in nitric acid, while silver chlorid would be insoluble in the 
nitric acid. The silver oxalate, dried and heated on platinum, 
disperses with a slight explosion and a white smoke. 

Lead Acetate Test. — With lead acetate a white precipitate of 



204 NON-METALS 

lead oxalate is formed which is soluble in nitric acid, but insoluble 
in acetic acid. 

Potassium Permanganate Test. — Mixed with potassium per- 
manganate and dilute sulphuric acid the oxalic acid is oxidized 
(H 2 C 2 4 + = 2C0 2 + H 2 0), and the permanganate, slowly losing 
its color, is converted into manganese sulphate. 

Sublimation Test. — Heated on platinum foil, the acid crystals 
slowly sublime at as low a temperature as ioo° C. (212 F.), and 
they are entirely and promptly dissipated at 160 ° C. (302 ° F.). 
At this temperature a large part is decomposed, first into formic 
acid and carbon dioxid. Thus: 

H 2 C 2 4 = H 2 C0 2 + C0 2 . 

Formic acid. 

The rising temperature then decomposes the formic acid into 
carbon monoxid and water. Thus: 

H 2 C0 2 CO + H 2 0. 

The potassium oxalate does not sublime* but changes to potas- 
sium carbonate, which effervesces when touched with an acid, and 
turns red litmus-paper blue. 

K 2 C 2 4 = K 2 C0 3 + CO 

Potassium oxalate. Potassium carbonate. Carbon monoxid. 

Detection. — The symptoms of corrosive poisoning from an acid 
liquid which has left no colored spots upon the skin would be 
significant. A strong solution makes on black cloth a dark- 
brown, uncorroded spot, which gives the oxalic acid reactions. 
The vomited matters should be searched for the leaves of sorrel 
or green material of the rhubarb pie; not that these are ever fatal, 
but so as to exclude the possibility of a complication in the anal- 
ysis. In the vomited matters and gastric contents the acid will 
be partly free, partly combined as soluble oxalate, and partly 
combined as the insoluble calcium or magnesium oxalates. If it 
should be mostly free, the following method will serve: 

1. Having made an extract with hot dilute hydrochloric acid 
and filtered it, add lead acetate, which will throw down the lead 
oxalate along with various other lead compounds. This deposit 
should be suspended in water and hydrogen sulphid passed through 
it for two hours. The oxalic acid is set free in solution, the black 
lead sulphid being thrown down. After separation by a filter the 
filtrate should be tested with calcium acetate. 

2. If the oxalic acid is in the combined state, the following 
is the better method: Digest the suspected matters with warm 



SILICON 205 

dilute hydrochloric acid until the mixture is quite fluid, filter, and 
to the filtrate add ammonium hydroxid until an alkaline reaction 
is reached. After standing the liquid is decanted and the deposit 
collected on a filter. This deposit is calcium oxalate. The fil- 
trate mixed with the decanted fluid is treated with excess of calcium 
acetate and the precipitate separated on a filter. This second 
deposit represents the free acid in the original material. To 
determine the nature and amount of the first deposit, it should be 
washed with acetic acid on the filter and afterward put into a 
beaker and dissolved by cautiously adding strong hydrochloric 
acid and gently heating. Excess of ammonia will precipitate it 
completely if sufficient time is allowed. After decanting the clear 
fluid the deposit is washed by decantation, put into a tared dish, 
dried in a water-bath, and weighed. If this deposit is calcium 
oxalate, it will be white, and when a portion is heated on platinum, 
leave a gray ash of calcium carbonate. Another portion warmed 
in a test-tube with strong sulphuric acid evolves carbon dioxid gas, 
which can be identified by conducting it through a delivery tube 
into baryta water. A third portion, suspended in water slightly 
acidulated with sulphuric acid, will discharge the purple color of 
potassium permanganate. This test can be applied by standard 
volumetric solutions and an estimate of quantity obtained. 

If the poison has been taken as neutral sodium or potassium 
oxalate, the local symptoms and pathologic changes may not be 
at all characteristic. The effects come on after absorption and 
are mainly systemic. To make a complete examination the poison 
must be looked for outside the alimentary canal, by separating it 
from the urine and the finely divided tissue of the kidney. The 
method would be the same as that for vomited matters containing 
the combined acid. 

SILICON (Silex, a flint) 

Symbol, Si. Atomic weight, 28. 

Properties. — Silicon is a tetrad element like carbon, never 
found native, but combined with oxygen as silica, Si0 2 . Silica 
exists nearly pure in rock crystal or quartz, in sand, flint, and 
many minerals, and is also found combined with the metals as 
silicates. Silicon, next to oxygen, is the most abundant element 
known. It resembles carbon in physical and chemical properties. 
Like carbon it has three modifications, viz.: 

Amorphous — a brown powder, only acted upon by hydrofluoric 
acid, HF, which dissolves it. 

Graphitoidal — hexagonal plates with metallic luster. 

Adamantine — in steel-gray crystals, hard enough to scratch 
glass. 



206 NON-METALS 

Silicic Anhydrid, Silicon Dioxid (Si0 2 ) {Silica). — Prop- 
erties. — It is a snow-white, gritty, insoluble powder, almost 
infusible, but soluble in hydrofluoric acid, HF. It is prepared by 
heating metasilicic acid, H 2 Si0 3 : 

H 2 Si0 3 + heat = H 2 + Si0 2 . 

Silica also exists, in a crystallized form, as quartz. Joined to 
one or more molecules of water silica forms a series of acids, like 
the phosphoric acids, viz.: 

Metasilicic acid, Si0 2 + H 2 = H 2 Si0 3 ; and 

Orthosilicic acid, Si0 2 + 2H 2 = H 4 Si0 4 . 

Metasilicic acid (H 2 Si0 3 ) is a clear limpid fluid, in a colloidal 
solution, with a tendency to become gelatinous. It is the chief 
agent in petrifaction. It is prepared by acting upon potassium 
silicate, K 2 Si0 3 , with hydrochloric acid, HC1. Thus: 

K 2 Si0 3 + 2HCI = 2KCI + H 2 Si0 3 . 

Orthosilicic acid (H 4 Si0 4 ) is a white gelatinous substance when 
first precipitated, and soluble until evaporated to dryness. It is 
prepared by leading silicon tetrafluorid, SiF 4 , into water. Thus: 

3 SiF 4 + 4 H 2 = 2H 2 SiF 6 + H 4 Si0 4 . 

Orthosilicic acid results, together with a new acid, H 2 SiF 6 , to 
which the name of hydro flu silicic acid is given. 

Most of the silicates found in nature are derived from meta- 
silicic acid, H 2 Si0 3 , to which the normal or orthosilicic acid reverts 
when it is set free, H 4 Si0 4 losing H 2 0, becoming H 2 SiO s . 

Glass. — Silicates of the alkaline metals are soluble, one of 
them, known as sodium water-glass, is official as liquor sodii 
silicatis. This is prepared by fusing together sand and dry sodium 
carbonate: Na 2 C0 3 + Si0 2 = Na 2 Si0 3 + C0 2 . Dissolving in boil- 
ing water to make a thick liquid it can be used as a cement or 
artificial stone. It loses water rapidly and becomes a glass. When 
bandages and fracture dressings are covered with it they soon 
harden and make an immovable apparatus. To remove them 
hot water must be applied. 

Common glass is a silicate of calcium and sodium, lime being 
introduced with sodium carbonate to make the glass insoluble. 

Hard German, or Bohemian glass, is made with sand, lime, and 
potassium carbonate. It stands heat better than the soft French 
glass, of which chemical apparatus is usually made. 

Soft French glass is a silicate of calcium, sodium, and alumin- 
ium. 

English flint glass, used for optical purposes and ornamental 
cut glassware, has the calcium replaced with lead. It is more 
fusible and has a higher refracting power for light rays. 



SILICON 207 

Silicon hydrid (SiHJ is a colorless gas, taking fire spontane- 
ously in the air, forming water and white cloud rings of silica. 

Silicon tetrafluorid (SiF 4 ) is a colorless, pungent gas, fuming 
in air, and is formed when hydrofluoric acid comes in contact 
with silica. It is prepared by heating fluorid of calcium with 
sand or silica and sulphuric acid: 

2 CaF 2 + Si0 2 + 2H 2 S0 4 = 2CaS0 4 + 2H 2 + SiF 4 . 

It is decomposed by water, but may be collected over mercury, 
or by displacement. A corresponding compound with bromin is 
known, called Silicon bromid, SiBr 4 . 

Silicon tetrachlorid (SiClJ is a colorless, pungent, irritating 
liquid, formed when silicon is heated in chlorin. 

Silicon resembles carbon in the composition of its salts. Thus: 

C0 2 H 2 CO s CH 4 CC1 4 . 

Si0 2 H 2 SiO s SiH 4 SiCl 4 . 

But the two elements also differ widely in some respects. While 
both form many compounds, the carbon derivatives have a struc- 
ture showing very different relationships to the carbon from those 
of the silicon derivatives to that element. Carbon compounds 
appear to be derived from the hydrocarbons; silicon compounds 
arise from or are related to silicon dioxid. 

Carborundum. — At the very high temperature of 3500 C. 
obtained in an electric furnace, the following reaction occurs in a 
mixture of carbon, sand, and salt: 

Si0 2 + 3C SiC + 2CO. 

The greenish-black mass SiC is called technically "carborundum." 
It is used as a grinding material, being of sufficient hardness to 
replace the diamond in glass cutting. It resists the strongest acids, 
but decomposes by fusion with alkalis. 

" Weathering " of Rocks. — It is a remarkable fact that 
the stable and insoluble silicates in granite and other primitive 
rocks when exposed to the air break up into loose soil and sol- 
uble carbonates, by displacement of the silicic acid in their con- 
stituents with the carbonic acid of the air. This result of weather- 
ing makes resistant minerals turn to sources of fertility, as the 
alkaline carbonates thus liberated are necessary to plants. A proc- 
ess imperceptible in any laboratory experiment, with the small 
mass of carbonic acid ordinarily engaged, becomes on the large 
scale of nature and in geologic time a reaction of great importance, 
owing to the enormous quantities of carbonic acid in the air and 
surface waters unceasingly at work. 



208 NON-METALS 

BORON 

Symbol, B. Atomic weight, n. 

Properties. — Boron is a triad element which is never native, 
but is found united with oxygen and sodium as borax; and with 
oxygen alone as boron trioxid. It occurs in three modifications: 

Amorphous boron — a dull gray powder which, when strongly 
heated in air, burns to boric oxid, B 2 3 . 

Graphitoidal boron, in scales with graphite-like luster. 

Diamond boron is square octahedra of cupreous luster; hard 
enough to scratch a ruby. 

Boron, when heated strongly in chlorin or oxygen, takes .fire, 
forming a chlorid or oxid. It is remarkable as being one of the 
few elements uniting directly with nitrogen, which gas it absorbs 
when red hot with the evolution of light, forming boron nitrid, BN. 
Boron with chlorin forms a liquid called boron trichlorid, BC1 3 ; 
with hydrogen a trihydrid, BH 3 . 

Boron Trioxid, Boric Anhydrid (B 2 3 ) — This compound 
fuses to a glass, which retains its clearness on cooling. It is pre- 
pared by heating boric acid, H 3 BO s : 

2H3BO3 = 3 H 2 + B 2 3 . 

By reversing the reaction with water B 2 3 forms boric or boracic 
acid, H3BO3. 

Boric acid is a tribasic weak acid, crystallizing in pearly 
plates from a hot solution as it cools. It is found in the fumerolles 
(steam jets) which are constantly escaping from the earth in old 
volcanic districts of Tuscany, and in the lagoons which collect at 
the mouth of these jets. The boric acid is concentrated by the 
heat of the natural steam jets, and is finally obtained pure by 
crystallization. Sodium borate also occurs in California and 
Thibet. 

Preparation. — Boric acid may be prepared by the action of 
hydrochloric acid, on a hot solution of borax, Na 2 B 4 7 : 

Na 2 B 4 7 + 2HCI + 5H 2 = 2 NaCl + 4H 3 B0 3 . 

A 10 per cent, ointment is official. 

Borax is the salt most largely used in the arts. 

Borax (Na 2 B 4 7 ioH 2 0) (Biborate of Soda). — This substance is 
a native salt, but can be artificially prepared by heating together 
boric acid and sodium carbonate: 

4H3BO3 + Na 2 C0 3 = 6H 2 + C0 2 + Na 2 B 4 7 . 



BOROX 



209 



Borax is a salt of a tetraboric acid, formed from the normal 
acid, H3BO3, by loss of water. Thus: 4H3BO3 deprived of 5H 2 
yields H,B 4 7 . Borax is much used as a blow-pipe reagent in 
the laboratory, since many metallic oxids are soluble in fused 
borax, yielding colored glasses. It is also used as a flux to clean 
metals when they are to be soldered with hard solder. 

Its solution has an alkaline reaction and is largely used in 
medicine locally to destroy bacteria. 

Liquor antiseptic us (U. S. P.) is a solution of boric acid and 
thymol in a diluted tincture of aromatic oils. 

Toxicology of Boric Acid and Borax. — The local effect of 
boric acid being very mild, its virtues as a bactericide have led to 
its use in surgical practice, especially for washing out cavities and 
sinuses to prevent septic changes. Cases are recorded of depres- 
sion and eruptions of erythema and urticaria following its absorp- 
tion from wounds and cavities when used too freely. Occasionally, 
graver phenomena have appeared, such as vomiting, diarrhea, 
bloody urine, and collapse. Fatal results have ensued in a few 
cases from injecting the solution into the abscess sacs and from 
washing out the stomach with it. 

The toxicology of boric acid and borax is limited practically to 
the use of these agents as preservatives of food. They destroy the 
germs of fermentation and putrefaction in solid and liquid foods. 
For meats they are often mixed with salicylic acid and applied ex- 
ternally. For preserving milk it is a common practice to add to 
1 qt. of milk 10 gr. of a mixture of equal parts of borax and boric 
acid. 

Experiments upon men, conducted by the U. S. Agricultural 
Bureau, proved that "both boric acid and borax, when contin- 
uously administered in small doses for a long period, or when 
given in large quantities for a short period, create disturbances of 
appetite, of digestion, and of health." Even in the small amounts 
required for preserving cream and butter, and that used as an 
external dust on hams and bacon, which have to be transported 
long distances, both boric acid and borax are objectionable from 
a sanitary standpoint, unless the food substances are frankly 
labeled as preserved. 

As these substances are not normal constituents of the body, 
it is best to avoid their use, since the most conclusive evidence has 
been adduced that they are not free from harm in the amounts 
as commonly used for preserving food. 

Detection of Boric Acid in Meat. — Jorgenseri's test makes use 

of the property of neutralized boric acid to take on an acid reaction 

after treatment with glycerin. The meat is made strongly alkaline 

with sodium hydroxid, extracted with hot water for several hours, 

14 



2IO THE METALS 

and the extract filtered. The filtrate is evaporated to dryness, 
incinerated, and the ash dissolved in sulphuric acid by warming, 
the carbon dioxid is removed, and on cooling the solution is neutral- 
ized by an alkaline hydroxid, using phenolphthalein as indicator. 

To 50 c.c. of the neutral fluid 25 c.c. of glycerin are added, 
and the mixture titrated with decinormal sodium hydroxid solu- 
tion without regard to the phosphates. The end-reaction is made 
more definite by the addition of ethyl alcohol. 

Detection in Milk. — Turmeric Test. — Place in a porcelain dish 

1 drop of the milk with 2 drops of strong hydrochloric acid and 

2 drops of a saturated turmeric tincture. Dry this on a water- 
bath, cool, and add a drop of ammonia by means of a glass rod. 
A slaty-blue color changing to green is produced if borax is present. 
A drop of milk containing nnnr g r - °f borax will give this reaction. 

Flame Test. — With alcohol boric acid forms a volatile ester 
which burns with a green flame. Material suspected of containing 
boric acid is put in a capsule and covered with sulphuric acid. 
Alcohol is poured over the mixture, which is heated until it takes 
fire. The green color is very characteristic. 



THE METALS 

The metals are easily recognized by properties common to all 
and illustrated in well-known examples, such as gold, silver, cop- 
per, and lead. All except mercury are solid at ordinary temper- 
ature. They conduct well both heat and electricity, and many 
can be polished so as to reflect light, this quality being described 
as metallic luster. Most of them are dense and heavy, can be 
drawn into wires {ductile), hammered into thin plates {malleable), 
and resist attempts to break them {tenacious). All are opaque 
except when reduced to the thinnest films, such as gold-leaf. 
When metals combine among themselves they make alloys; if the 
union be with mercury, it is called an amalgam. These combina- 
tions are not attended by loss of metallic character. 

When solutions of metallic salts are put in electrolytic cells 
the metals invariably seek the negative pole, and hence are cations. 

In the present work a classification is adopted deemed suitable 
for the needs of the medical student. The resemblances which 
are emphasized and which form the basis of the groups are such 
as have significance growing out of their medical or toxic rela- 
tions. Several very different arrangements are possible, which 
might be regarded as more suggestive and more helpful to the 



METALS OF THE ALKALIS 211 

non-medical students of chemistry, because they include a greater 
number of analogies. One of these is the natural system referred 
to on p. 116. 

The important metals will be considered in the order of the 
following groups, the lightest metals presenting the highest powers 
of uniting with oxygen: 



I. Alkali metals : oxids and most salts soluble. 1 Light metals with spe 

II. Alkaline earth metals : oxids soluble, carbonates [ cific gravity not ex- 
insoluble. 

III. Earth metals : oxids insoluble. 

IV. Arsenic group: sulphids insoluble in dilute acids, 

but soluble in ammonium sulphid. 
V. Copper group : sulphids insoluble in dilute acids, 
and in ammonium sulphid. 
VI. Iron group : sulphids soluble in dilute acids. 
VII. Gold group : sulphids insoluble in dilute acids, 
but soluble in ammonium sulphid. 



ceeding 4. Sulphids 
soluble in water. 



Heavy metals with 
specific gravity ex- 
ceeding 4. Sulphids 
insoluble in water. 



THE LIGHT METALS 
L— THE METALS OF THE ALKALIS 

Potassium, K. Ammonium, NH 4 , hypothetic. 

Sodium, Na. Cesium, Cs. 

Lithium, Li. Rubidium, Rb. 

The members of this group are all univalent, some of them 
are lighter than water, and nearly all of their compounds are 
soluble in water. They never occur free in nature, because of 
their great power of forming compounds. This also makes it 
necessary to resort to unusual precautions to protect them from 
such union. Their oxids, hydroxids, and carbonates are alkaline 
in reaction. None of the group reagents has any visible effect 
upon solutions of the salts belonging to this group. Their chlo- 
rids and sulphids are all soluble and, therefore, are not precip- 
itated by hydrochloric acid, hydrogen sulphid, or ammonium 
sulphid. Unlike the alkaline earths, they (except lithium) are 
not precipitated by ammonium carbonate. 

Corrosive Alkalies. — Under this heading will be considered 
the hydroxids or hydrates of potassium, sodium, and ammonium. 
It is well to note that their basic carbonates also are not only strongly 
alkaline in reaction, but in concentrated solution have a corrosive 
effect. The action of the corrosive alkalies is chemical or local, 
and limited to the part with which they come in contact. This 
corrosive power is due to their solvent action on albumin, their 
saponifying property when mixed with fatty matter, and their 
avidity for the water of the tissues. They cause rapid and deep 
destruction of the animal structures. The local symptoms are 



212 THE METALS 

like those of corrosive acids. The general symptoms are likewise 
those of the shock of a violent lesion added to the immediate 
consequences of the lesion due to its locality. Poisoning from them 
is most often accidental, though they are not infrequently taken 
with suicidal intent. 

POTASSIUM (Kalium) 

Symbol, K. Atomic weight, 39.14. 

Occurrence. — Potassium is found in nature in its compounds 
only. Among these are saltpeter, feldspar, and carnallite. The 
disintegration of feldspar by the weather furnishes the soil with 
potash in a form assimilable by plants, required by them for their 
growth, they in turn furnishing it in vegetable food to animals. 
In small quantities potassium is indispensable to the animal 
organism, being a constituent of the red blood-corpuscles. When 
greatly concentrated many of its salts act as irritants or cor- 
rosives. Even if diluted, the continuous administration of these 
salts in full doses brings about anemia, loss of energy, and other 
indications of impaired nutrition. This toxic action is attributable 
to the potassium ion in the blood in excess of the physiologic 
need. 

The ashes of wood, leached with water, yield potassium car- 
bonate; the water evaporated by boiling leaves crude potash, 
formerly the chief source of the other compounds. 

Preparation. — Potassium is now prepared by decomposing 
the hydroxid or chlorid by electricity, K*, C1'=K+C1. The 
older chemical method was to heat potassium carbonate with 
charcoal. The carbonate yields oxygen to the reducing carbon 
to form the gas carbon monoxid, and the metal is vaporized to 
condense under petroleum. Thus: 

K 2 C0 3 + 2C = 2K + 3CO. 

Properties. — Freshly cut surfaces of potassium show a silver- 
white luster. At ordinary temperatures it is soft, like wax, and 
can be molded by the fingers. At a red heat it passes into 
a blue-green vapor. It combines with oxygen with so much 
velocity that it decomposes water violently, and, exposed to the 
air, tarnishes immediately. For protection potassium must be 
kept under petroleum or in hydrogen gas. In time, even in coal- 
oil, it unites with some dissolved oxygen and becomes covered 
with a gray-brown crust, which, however, shields the deeper parts. 

Potassium Dioxid (K0 2 ).— This is prepared by heating 
potassium in oxygen. It is an orange-colored powder used to 
form hydrogen dioxid. 

2K0 2 + 2H 2 = 2KOH + H 2 2 + 2 . 



POTASSIUM 213 

Potassium Hydroxid (KOH) (Potassium Hydrate, Caustic 
Potash). — Preparation. — When thrown upon water, a piece of 
potassium floats about on the surface, melts, forms a silvery ball, 
bursts into a reddish-violet flame, and grows red hot. As the 
metal is consumed the flame goes out, the incandescent ball of 
hydroxid cools down to the point when wetting is possible, and 
then dissolves with such a sudden evolution of heat that a steam 



Fig. 59. — -Potassium decomposing water. 

explosion occurs. The violet or lavender flame is hydrogen ignited 
by the heat of chemical action and colored by particles of potas- 
sium (Fig. 59). 

H 2 +- K = KOH + H. 

Commercially it is manufactured by first electrolyzing potassium 
chlorid, using a cathode of mercury. The mercury makes an 
amalgam with the potassium, and the amalgam, in contact with 
water, forms the hydroxid, the free mercury being again ready for 
use as a cathode. 

If mercury be not used as a cathode, the movement of the ions 
occurs in the sense of the following equation: 

K",C1' + H-,(OH) / = H + CI + K',(OH)'. 

The chlorin ions give up their charge at the anode and escape 
as gas. The potassium ions seek the cathode with a strong charge; 
there they find some of the weakly dissociated hydrogen ions of 
the water, which discharge upon the cathode and are set free as 
gas. The remaining hydroxyl anions are held in relation to the 
potassium cations as potassium hydroxid in solution. 

The older method of preparation was to decompose potassium 
carbonate with calcium hydroxid in weak solution. The reaction 
is expressed thus: 

K 2 C0 3 + Ca(HO) 2 = CaC0 3 .+ 2KOH. 

The calcium carbonate is precipitated, and the potassium hydroxid 
is separated by boiling off the water of the filtered solution. 



214 THE METALS 

Properties. — The pure substance is a gray-white solid with an 
angular fracture. It imparts a soapy feeling when handled, has 
a soapy taste, and a strong alkaline reaction to litmus. Heated, 
it melts to a colorless liquid; run into cylindric molds it makes 
potassa fusa, the ordinary form seen in shops. It dissolves in 
half its weight of water, evolving heat; it is souble also in 
alcohol and glycerin, but insoluble in ether. It deliquesces 
rapidly, and in the moist state freely takes up carbon dioxid gas 
to make potassium carbonate. It is a typical base, dissociating 
strongly and developing in a high degree the alkaline properties 
of hydroxidion. A very small quantity in solution makes litmus 
blue and phenolphthalein red. 

Pharmaceutic Preparation. — Potassii hydroxidum occurs in 
cylindric rods. Liquor potassii hydroxidi (U. S. P. ) is a color- 
less, acrid, alkaline, corrosive liquid with a specific gravity of 
1.036, and containing about 5 per cent, of potassium hydroxid. 
Potassa cum calce (Vienna paste) is made of equal parts of potassa 
and quicklime. The two carbonates resemble the hydroxid in 
toxic effects, but differ in degree. Potassii carbonas impura (pearl- 
ash), under the name of potashes, used for cleansing oil-lamps, 
occurs as a dark mass, deliquescent, strongly alkaline, and caustic. 
Potassii carbonas pura occurs as white crystals, deliquescent, 
alkaline, and caustic. 

Symptoms. — Taken in strong solution, a large dose of caustic 
potash or the carbonate will cause a nauseous, soapy taste, accom- 
panied by burning pain in the mouth, throat, and stomach. Vomit- 
ing of alkaline bloody material soon follows, and later colicky 
pains and great abdominal tenderness with purging of shreds of 
epithelium, mucus, and blood. The lips and tongue swell and 
turn brown, swallowing is difficult, and the skin cold and damp, the 
breathing hurried and shallow. Surviving these symptoms, the 
patient may die after some days of starvation from stricture of the 
gullet. 

Fatal Dose. — The ordinary fatal quantity is \ oz. (15.5 gm.), 
but 30 gr. (2 gm.) have proved sufficient. 

Fatal Period. — From the acute effects death may come in three 
hours; from the secondary effects the final event may be delayed 
for weeks or even years. The average duration is about twenty- 
four hours. 

Treatment. — The local action of the poison should be lessened 
by copious drafts of water, alone or acidulated. The chemical 
antidotes are weak acids and oils. The most convenient weak 
acid is vinegar, but diluted lemon-juice or orange-juice will serve. 
Milk, olive oil, melted butter, or lard would also neutralize the 
alkaline, though not so promptly. The stomach-pump is not admis* 



POTASSIUM 215 

sible. The pain will call for morphin injections; collapse should 
be met by stimulants, and threatened starvation by nutritive 
enemata. 

Postmortem Appearances. — The mouth, throat, and gullet are 
whitish and softened. The stomach and intestines are bright red 
or black from extravasated blood; the lining membrane dis- 
organized and stripped in patches. The secondary pathologic 
changes seen when death closes the history of a chronic case are 
denudation of the lining membrane, ulceration, and points of 
stricture in gullet or pylorus. 

Detection. — As alkalinity of the gastric contents has never been 
reported in any normal case, the mere fact that vomited matters 
or gastric contents have an alkaline reaction would be so excep- 
tional as to be suspicious. After separating the soluble alkali 
from the undissolved matter by dialysis, the clear liquid should 
be titrated with decinormal sulphuric acid and tested for potassium 
(see p. 222). As the chlorid, sulphate, and phosphate of the metal 
are natural constituents of the food and of the body itself, more or 
less of these will be found always present. Hence if the fluid is 
not alkaline, the process must include quantitative determinations 
of the different metals. If the analyst can obtain a sample of the 
substance taken or a piece of the clothing stained, his task is 
much simpler. 

Potassium chlorid (KC1) is found in Germany in the mineral 
carnallite. It is a double chlorid of magnesium and potassium. 
To obtain the potassium chlorid from this mineral a hot solution 
is made, which on cooling separates the potassium chlorid as 
crystals. 

Properties. — Potassium chlorid forms white cubic crystals much 
more soluble in hot water than in cold. It is typical of the salts 
formed by a strong acid, HC1, acting on a strong base, KHO, 
and in solution its ions are completely dissociated. 

Potassium bromid, KBr, can be formed, as other bromids, 
by the direct action of bromin on the metal, though the more con- 
venient method is action on the hydroxid: 

6KOH + 6Br = 5KBr + KBr0 3 + 3H 2 0. 

Properties. — It crystallizes in white cubes without odor, but 
with a salty and nutty taste. It is soluble in about 2 parts of 
water, 4 of glycerin, but requires 200 of alcohol. Its solution is 
a convenient source of bromin ions. Dose: 15 to 60 gr. (1-4 
gm.), repeated. If long continued, there is danger of inducing 
bromism (see p. 144). It is incompatible with acids, alkaloids, and 
the salts of silver, mercury, lead, copper, bismuth, and antimony. 



2l6 THE METALS 

Potassium iodid, KI, is prepared by a reaction between 
potassium hydroxid and ferrous iodid: 

Fel 2 + 2KOH = Fe(OH) 2 + 2KI. 

The ferrous hydroxid is precipitated, the potassium iodid remains 
in the nitrate. 

Properties. — It occurs in white cubes of a bitter, salty taste, 
soluble, 1.27 parts in 1 of water, in glycerin 1 part to 3, in alcohol 1 
to 18. Dose: 3 to 30 gr. (0.19-1.9 gm.), repeated. Care should be 
observed lest iodism be induced (see p. 147). The ion of iodin is 
well represented in the aqueous solution. It is incompatible with 
acids, metallic salts (especially silver nitrate, calomel, and potas- 
sium chlorate), chloral hydrate, and salts of alkaloids. 

Potassium chlorate (KC10 3 ) is obtained when chlorin acts 
on potassium hydroxid: 

6KOH + 6C1 = 5KCI + KCIO3 + 3H 2 0. 

Of the two salts the chlorate is less soluble, and on evapora- 
tion of the mixed solution it crystallizes first. 

Properties. — Its crystals are beautiful white plates with a cool 
saline taste, soluble in about 17 parts of water, insoluble in alco- 
hol. In the laboratory it is chiefly valuable as a store of oxygen, 
which it readily yields on heating. Dose: 10 to 20 gr. (0.64- 
1.29 gm.), diluted, after meals. Tablets for sore mouth, 5 gr. 
each. It is incompatible with tartaric acid and ferrous iodid. It 
is likely to explode when rubbed in a mortar with sugar, sulphur, 
or phosphorus. 

This salt is much used in the manufacture of explosives and 
flashing powders, and in medicine. In the household it is a com- 
mon remedy for sore mouth and throat, and through a belief in 
its harmlessness, often leads to injury. 

Symptoms. — If used as a mouth-wash it is harmless, but when 
swallowed in large doses it is irritant, causing abdominal pain, 
vomiting, diarrhea, and even collapse. A case of poisoning has 
been reported from two teaspoonfuls taken in two days for sore 
throat. It caused violent intestinal irritation, with black stools, 
considerable urinary disturbance, with black urine, great prostra- 
tion, and evidences of grave alteration of the blood. 

When absorbed, it has a peculiar destructive action on the red 
corpuscles of the blood, converting the hemoglobin into methemo- 
globin and setting up secondary symptoms, such as jaundice, 
hemoglobinuria, suppression of urine, bloody tube-casts, delir- 
ium, coma, and death as a consequence of the acute nephritis. 



POTASSIUM 217 

Fatal Dose and Period. — Forty-six grains (2.9 gm.) proved a 
fatal dose in a child three years old. The minimum adult dose 
reported as fatal is 3 dr. (11.65 gm.). Fountain took ij oz. with 
fatal consequences in seven days. If a certain amount is given 
in divided doses, the effect is more severe than when given in a 
single dose. Death has occurred in five hours, but usually it 
results from nephritis after several days. 

Treatment. — Having washed out the stomach with the tube or 
pump, the secondary effects must be combated with appropriate 
remedies. The kidney complications will require active local 
treatment. 

Postmortem Appearances. — The marks of gastro-enteritis will 
be found — i. e., a mucous membrane reddened, thickened, and 
easily detached. Inflammatory changes are seen in the spleen, 
liver, and especially in the kidneys. These organs are enlarged 
and dark brown in color, from the presence of the altered hemo- 
globin. 

Detection. — As the salt is unchanged in the body, it can easily 
be separated from organic matter by dialysis. Having colored 
the suspected solution with indigo sulphate and acidulated with 
dilute sulphuric acid, the addition of sulphurous acid will discharge 
the blue color if the chlorate be present. 

Potassium nitrate (KNO s ) (saltpeter, niter) is found in the 
soil of India and can be procured by leaching with water. It is 
also formed artificially in "plantations" of bacteria. Nitrogenous 
waste of animals mixed with the potassium carbonate of wood 
ashes make a soil for the growth of the nitrifying bacteria. These 
ferments cause the ammonia of putrefaction to be oxidized to nitric 
acid, which unites with the potassium of the wood ashes to form 
KNO3. After several years the fermenting material is leached 
and the crude nitrate dissolves out, to be purified by crystalliza- 
tion. Like the chlorate, this salt is a liberal oxidizer. 

In 100 parts of gunpowder there are of KNO s 75 parts; sul- 
phur, 12 parts; carbon, 13 parts. Owing to the intimacy of the 
mixture, combustion is immediate and complete. It is explained 
in part according to this equation: 

2KNO3 + 3C + S = K 2 S + 3C0 2 + N 2 . 

Properties. — It forms large hexagonal prisms, permanent in the 
air. Without odor, they have a cool saline taste, and are soluble 
in 4 parts of water. Dose: 10 to 60 gr. (0.65—4 gm.). 

Charta potassii nitratis is paper dipped in a saturated solution 
and dried. It makes a " touch paper," the smoke of which, on 
burning, is inhaled for the cure of asthma. 



2l8 THE METALS 

Under the name sal prunelle potassium nitrate is found to be 
molded in small balls. It is used as a remedy for the diseases of 
cattle; also in the preservation of the original reddish color of 
salted meat and in the manufacture of explosives. In the crystal- 
line form it has been taken as a purgative by mistake for mag- 
nesium sulphate in 8 cases. In 2 cases it has been mistaken for 
common salt. 

Symptoms. — While doses of 1 dr. (4 gm.) cause minor degrees 
of gastric and intestinal irritation, doses of from i to 1 oz. (16- 
32 gm.) excite acute gastro-enteritis. There are vomiting, abdom- 
inal pain, diarrhea, perhaps bloody in character, localized 
muscular spasms, disturbed respiration and heart action, and col- 
lapse. 

Fatal Dose. — Though an adult has died from the effects of 
2 dr., other cases have recovered from a dose of 1 oz. 

Fatal Period. — Two hours is the shortest period in which death 
has taken place; the average duration of fatal cases is somewhat 
longer. 

Treatment. — The stomach must be evacuated by emetics, and 
the stomach-pump or tube used to wash out the poison. Bland 
demulcents may be administered, and the tendency to collapse 
overcome by stimulants and warm applications. 

Detection. — As nitrates are not present in the body, the presence 
of a notable quantity in the gastric contents or other organic 
mixture would be significant. By adding sulphuric acid the 
nitric acid is freed and the tests for the acid can be applied (see 
p. 172). 

Copper Tests. — Heated in a test-tube with sulphuric acid 
and copper turnings, nitrates evolve red fumes of nitrogen oxids. 

Brucin Test. — Mixed with an equal volume of sulphuric acid, 
a nitrate solution produces a tint of carmin on the addition of a 
trace of brucin. 

Potassium Nitrite (KN0 2 , H 2 0).— This is formed when 
part of the oxygen of potassium nitrate is liberated by heating: 

2KNO3 = 2 KN0 2 + 2 . 

When the nitrate is employed to oxidize metals, such as lead, 
the nitrite is also obtained as the reduced salt: 

KNO3 + Pb = KN0 2 + PbO. 

The aqueous solution of this sale of a weak acid is alkaline 
from the preponderance of hydroxyl ions caused by the hydro- 
lysis, the acid being almost undissociated: 

K-, (N0 2 )' + H 2 = K-, (OH)' + HNO,. 



POTASSIUM 219 

The nitrous acid, HN0 2 , is set free in solution when sulphuric 
acid is added to a solution of potassium nitrite. Its anhydrid is 
N 2 3 . 

Potassium hydrosulphid, KHS, is formed by saturating a 
solution of potassium hydroxid with the gas hydrogen sulphid: 

KOH + H 2 S = H 2 + KHS. 

As a salt of sulphydric acid, which is weak in its acid proper- 
ties, hydrolytic dissociation occurs, forming hydroxidion in amounts 
dominating the hydrion, which is scarcely dissociated from the 
acid, and, therefore, making an alkaline solution. Thus: 

K', (HS)' + H 2 = K-, (HO)' + H-, (HS)'. 

Potassium monosulphid, K 2 S, as a hydrolyzed alkaline solu- 
tion, is obtained by adding potassium hydroxid to potassium 
hydrosulphid: 

KHS + KOH = K 2 S -1- H 2 0. 

Four other sulphids are known, the higher polysulphids being 
interesting as components of the medicinal compound. Potassii 
sulphuratum, hepar sulphuris, or liver oj sulphur, is the product 
obtained by fusing together potassium carbonate and sulphur. 
It is a brownish-yellow mixture of sulphids, varying in composi- 
tion between the trisulphid, K 2 S 3 , and the pentasulphid, K 2 S 5 . 
Dose: i to 5 gr. (0.03-0.3 gm.). 

Potassium sulphate, K 2 S0 4 , occurs in combination with 
magnesium chlorid in the mineral kainite, and also in mineral 
waters. Its hard prismatic crystals have a bitter, salty taste, are 
permanent in the air, and are soluble in 10 parts of water. It is 
a laxative in doses of 20 to 120 gr. (1-5 gm.) in solution. In 
excessive doses it has proved poisonous, causing abdominal pain, 
vomiting, purging, exhaustion, and fatal collapse. There is no 
specific antidote. The stomach should be evacuated and the 
irritation and depression treated as they arise. 

Potassium Acid Sulphate, or Potassium Bisulphate (KHS0 4 ). 
— This is obtained as a by-product in the manufacture of nitric 
acid. It is formed when the normal sulphate is treated with 
more sulphuric acid; hence the name bisulphate. 

K 2 S0 4 + K 2 S0 4 = 2 KHS0 4 . 

Its colorless, moist plates are freely soluble in water, making 
a strongly acid solution. This reaction is caused by the strong 



2 20 THE METALS 

acid, H 2 S0 4 , dissociating to a slight extent its unreplaced hydrogen. 
Thus : 

KHSO, = K-, H;, (SOJ". 

Potassium bisulphate is used in medicine as an aperient tonic. 
Dose: 60 to 120 gr. (3-5 gra.). 

Potassium Sulphite (K 2 SO s ). — This is formed by saturating 
with sulphur dioxid a solution of potassium carbonate or hydroxid. 
Evaporating the solution over sulphuric acid, the sulphite is 
obtained crystallized in rhombohedra. These crystals are soluble 
in water, and in solution change to K 2 S0 4 by absorbing oxygen 
from the air. The pyrosulphite, K 2 S 2 5 , oxidizes very slowly in 
air and is employed in photography. In water it makes an acid- 
sulphite solution containing the ions K* and (HS0 3 )'. 

Potassium carbonate, K 2 CO s , occurs in the animal body 
and in mineral waters. For many years it was produced by leach- 
ing with water the ashes of plants, and then boiling off the water. 
The impure potash or pearlash was purified by solutions and crys- 
tallizations, so as to make pure potassium carbonate. The modern 
method of preparation is to electrolyze potassium chlorid; the 
hydroxid forming in the liquid around the cathode. Carbon 
dioxid is passed into the hydroxid solution, forming potassium 
carbonate. 

Properties. — It is a white granular powder, deliquescent and 
remarkably soluble in water. At low temperatures, by evapora- 
tion, a salt crystallizes with the formula 2K 2 C0 3 , 3H 2 0. 

Owing to the weakness of carbonic acid, there is an interchange 
with the ions of water which dissociates a sufficient percentage of 
free hydroxyl ions to cause a strong alkaline reac'ion. The hydro- 
lysis is in accordance with this equation: 

K-, K-, (C0 3 )" + H 2 = K-, (HO)' + K', (HC0 3 )'. 

Owing to its caustic action, potassium carbonate is not given inter- 
nally, but in dilute solution is used externally. (See Toxicology 
of Potassium Hydroxid, p. 214). 

Potassium Acid Carbonate or Potassium Bicarbonate (KHCO s ). 
— This is obtained by saturating with carbon dioxid a solution of 
the normal salt: 

K 2 CO a + C0 2 + H 2 = 2KHCO3. 

In this operation the carbonate seems to take up another molecule 
of carbonic acid, H 2 C0 3 , and hence the name bicarbonate. On 
evaporation it crystallizes in rhombic prisms, much less soluble 



POTASSIUM 221 

than the carbonate, and almost insoluble in alcohol. The dilute 
aqueous solution is alkaline in taste and in reaction, in spite of 
the unreplaced hydrogen. This is explained by the hydrolysis 
converting the anion (HC0 3 )' into undissociated H 2 C0 3 , and set- 
ting free a few ions of hydroxyl: 

KHCO3 + H 2 = K-, (HO)' + H 2 CO s . 

Saleratus is a name given to the bicarbonate because when 
heated it yields C0 2 , the aerating gas of "soda biscuits": 



2KHCO, = KXOo + H 9 + CO 



If not used with other chemicals in yeast powders the residue in 
the bread is potassium carbonate, K 2 C0 3 , unwholesome because 
it irritates the stomach. 

It is used in medicine as an antacid and antilithic. Dose: 20 to 
60 gr. (1.3-4 gm.). Owing to its nauseous taste it is taken in an 
effervescent draught. 

Potassium citrate, K 3 C 6 H 5 7 .H 2 0, is a white, granular deli- 
quescent powder having a cool salty taste; it is soluble in an 
equal weight of water, and slightly soluble in alcohol. The solu- 
tion is neutral or feebly alkaline. Dose: 10 to 30 gr. (0.6-2 gm.). 

Liquor potassii citratis is a palatable preparation in which the 
alkaline taste of the salt is overcome by the more agreeable flavor 
of citric and carbonic acids. It is prepared by dissolving 8 parts 
of potassium bicarbonate in 50 of water, and 6 parts of citric acid 
in another 50 of water and mixing the two solutions. It is a feb- 
rifuge and diuretic. Dose: J to 1 fl. oz. (15-30 c.c). 

Mistura potassii citratis {neutral mixture) is an agreeable prep- 
aration of potassium citrate made freshly by adding to 100 parts 
of fresh lemon juice about 10 parts of potassium bicarbonate to 
neutralize the citric acid of the lemon juice. Dose: same as for 
liquor potassii citratis. The neutral potassium salts of the carbon 
acids, citric, acetic, and tartaric, are converted into alkaline carbo- 
nates, either in the blood or the intestines, and when eliminated 
by the urine give it an alkaline reaction. 

Potassii citras effervescens is a granular solid, containing 
20 per cent, of potassium citrate mixed with enough sodium 
bicarbonate with tartaric and citric acids to react when dissolved 
with disengagement of carbon dioxid and forming soluble neutral 
salts. 

Potassium acetate, KC 2 H 3 2 , is prepared by neutralizing 
acetic acid with potassium carbonate or bicarbonate. This is ob- 
tained as white crystals, or as granular powder, very deliquescent, 



222 THE METALS 

and having a saline taste. They are neutral or feebly alkaline in 
reaction, and feebly soluble in water and alcohol. Dose: 5 to 60 
gr. (0.3-4 gm.). 

Potassium tartrate (K 2 C 4 H 4 6 ) (neutral tartrate or dipotassic 
tartrate), is made by neutralizing the bitartrate with potassium 
carbonate. It is obtained in small white crystals or powder, 
deliquescent, of saline taste, freely soluble in water, giving a neu- 
tral reaction; it is almost insoluble in alcohol. Dose: J to 4 dr. 
(2-16 gm.). 

Potassium Bitartrate (KHC 4 H 4 6 ) (Acid Tartrate, Cream 
0) Tartar, Monopotassium Tartrate). — This is produced in the 
course of fermentation of grape juice. The alcohol precipitates 
impure or crude tartar, the argol of commerce. Dissolved in 
boiling water, decolorized and washed in hydrochloric acid, it is 
crystallized by evaporation into colorless rhombs, having a sour 
taste, soluble in 200 parts of water and 15 of boiling water, and 
almost insoluble in alcohol. Dose: 1 to 4 dr. (4-16 gm.). In 
ordinary doses diuretic and laxative; in excessive doses an irri- 
tant poison, causing gastric pain, vomiting, diarrhea, and collapse. 
There is no specific antidote; emetics followed by soothing reme- 
dies are always called for. 

Tests for Potassium Salts.— The detection of potassion K% 
depends upon its compounds of slight solubility formed with 
the anions of tartaric acid (HC 4 H 4 6 )'; of hydrochlorplatinic 
acid (PtQe)"; of hydrofluosilicic acid (SiF 6 )"; of perchloric acid 
(C10 4 )'; and the cobalt nitrite ion, CO(N0 2 ) 6 '". 

1. To a concentrated solution of a neutral potassium salt add 
a fresh strong solution of tartaric acid. The difficultly soluble 
bitartrate is precipitated white, more copiously if alcohol be added. 

2. Acidulate the potassium solution with a few drops of hy- 
drochloric acid and add platinum chlorid and alcohol. Yellow 
crystals of potassioplatinic chlorid form: 

2KCI + H 2 PtCl 6 = K 2 PtCl 6 + 2HCI. 

3. With potassium salts hydrofluosilicic acid slowly forms a 
translucent gelatinous precipitate, soluble in strong alkalies. 

4. Perchloric acid yields a white precipitate, insoluble in 
alcohol. 

5. With a neutral or slightly acic 1 potassium solution, sodium 
cobaltinitrite gives the yellow precipitate of potassium cobaltini- 
trite: (KN0 2 ) 6 CO(N0 2 ) 6 + H 2 0. 

6. The readiest test is the lavender or reddish-violet color im- 
parted to a Bunsen flame. As sodium is often present and gives 
a yellow color, which masks the potassium violet, it may be nee- 



SODIUM 223 

essary to eliminate the yellow by viewing the flame through cobalt- 
blue glass. This permits the potassium light only to pass through, 
appearing reddish in color. Viewed by the spectroscope the 
lavender flame is resolved into a dull-red band and a faint violet 
line (Fig. 19). 

SODIUM 
Symbol, Na. Atomic weight, 23.05. 

Occurrence. — Like the other alkaline metals, sodium is never 
found free in nature. If liberated and not protected, its activity 
causes it at once to unite with other elements. Its compounds, 
especially sodium chlorid, are very abundant and very soluble; 
hence, they are washed from many sources in large amounts by 
the waters flowing into the sea and lakes that have no outlet. 
Solid salt beds mark the place where salt lakes have evaporated. 
The vapors rising from the sea are borne inland, carrying into the 
air minute quantities of sodium chlorid. The sensitive spectro- 
scope shows the bright-yellow sodium line in almost every obser- 
vation, no matter what substance be examined. 

Preparation. — At one time the metal was obtained by distil- 
lation of the carbonate by means of heated carbon: 

Na 2 C0 3 + 2 C = Na 2 + 3CO. 

But the most economic process is based upon the principle used 
by Davy when he first liberated it from the hydroxid by electro- 
lysis. The electric current, generated by water power, is passed 
through fused sodium hydroxid, NaHO. At the cathode sodium 
and free hydrogen appear, the sodium, floating upon the hydroxid, 
is skimmed off; the oxygen escapes at the anode. 

Properties. — Metallic sodium is a soft plastic solid, its freshly 
cut surface shining with a silvery luster, which soon tarnishes in 
the air. To protect sodium from the oxygen of the air it is kept 
under petroleum, but a more volatile hydrocarbon, like benzine, 
is preferred, as it is more easily removed from the surface of the 
metal. Like potassium (though it is less violent) it has an ener- 
getic reaction with water: 

Na + H 2 = NaHO + H. 

Thrown upon water, its movements are so vivacious as to dissi- 
pate its heat to a point below that which ignites hydrogen. If 
filter paper be floated on the water and a small piece of sodium 
placed upon it, the hot globule formed cannot move, and so 
enough heat is retained to set fire to the evolved hydrogen. The 
sodium gives the characteristic yellow color to the hydrogen flame, 



2 24 THE METALS 

and the hydroxid dissolves in the water, giving it alkaline proper- 
ties, turning litmus blue and phenolphthalein red (Fig. 19). 

Sodium Peroxid (Na 2 2 ).— When sodium is heated in dry 
air the metal falls into a yellow hygroscopic powder. This is an 
oxid having the composition Na 2 2 . It is valuable as a means of 
preparing hydrogen dioxid for bleaching textile fabrics. Water 
containing it is alkaline and behaves as if it were a solution of 
hydrogen dioxid, in accordance with this equation: 

Na 2 2 + 2H 2 = 2 NaOH + H 2 2 . 

Sodium Hydroxid (NaOH) {Sodium Hydrate, Caustic Soda). 
— It has been stated above that when water acts on metallic 
sodium the hydroxid is produced. From the carbonate it is 
obtained by the action of lime-water, the calcium being precipi- 
tated as carbonate, the sodium hydroxid being left in solution: 

Na 2 CO s + Ca(OH) 2 = CaCO s + 2 NaOH. 

It is now largely manufactured by electrolysis of sodium chlorid 
with mercury as a cathode to take up the metal. The amalgam 
in contact with water forms sodium hydroxid. 

Properties. — The hydroxid occurs in gray-white masses or in 
molded sticks, closely resembling potassium hydroxid. Like that 
it is strongly alkaline in reaction, soapy in taste, fuses by heat, 
dissolves freely in water with evolution of heat, is deliquescent, 
and in the moist state absorbs carbon dioxid from the air, forming 
the carbonate. This carbonate is not deliquescent, like potassium 
carbonate, but efflorescent. When a can of caustic soda is opened, 
the solid first liquefies, then absorbs carbon dioxid, and finally 
solidifies in a whitish powder. 

Under the name of "concentrated lye," an impure mixture of 
the hydroxid and the carbonate is largely used as a rapid cleanser 
in the laundry and in the making of soap. A child, in playing 
about the laundry, out of curiosity eats some of the contents of a 
can containing "lye." The poison, if it does not reach the stomach, 
corrodes the throat and leaves a stricture of the gullet, which per- 
mits swallowing of liquid food only. 

Symptoms. — The symptoms are those of a corrosive poison, 
differing in degree only from those caused by potassium hydroxid. 

Fatal Dose. — About the same as for the potassium compounds. 

Fatal Period. — The duration of life will depend on the dose and 
the lesions, and may be described as about the same as that given 
for the potassium compounds. 

Treatment. — The antidotes are water containing vinegar and 



SODIUM 225 

lemon juice to neutralize the alkali, and milk, oil, or butter to 
saponify it. 

Post-mortem Appearances. — The toxic effect is purely local. 
Although less active than the potassium compounds, the caustic 
forms of soda dissolve the albumin of the tissue, abstract the 
moisture, saponify the fatty material, and corrode deeply and 
widely. 

Detection. — The history of the case, inspection of inflamed 
spots on the face and hands, the strong soapy taste, and marked 
alkaline reaction of vomited matters will go far to prove a caustic 
alkali. The tests for sodium salts (see p. 229) can be applied to 
determine the character, making allowance for the sodium chlorid 
always present in food and tissue. As commercial sodium hy- 
droxid nearly always contains a small quantity of arsenic, a trace 
of the latter would strengthen the evidence in favor of the caustic 
alkali. 

Sodium chlorid, NaCl, common or table salt, is a type 
of neutral salts in general. Present everywhere in nature, it is 
essential to the process of nutrition in living things. While 
potassium is found in the blood-corpuscles, sodium salts are 
constituents of the plasma and other animal fluids. Rock salt 
is a mineral deposited at the bottom of salt lakes in former geo- 
logic eras. As obtained from the salt mines, it is colored by a 
trace of iron or other impurity. 

Properties. — From salt waters it separates as cubic crystals 
enclosing a drop of the salt solution. When heated the drop 
passes into vapor, bursting the crystal with a crackling noise. It 
is freely soluble alike in cold or hot water, insoluble in absolute 
alcohol. 

Normal salt solution is a solution of sodium chlorid (0.6 to 0.7 
per cent.). It is made by dissolving 45 or 50 gr. of common salt 
in 1 pt. of water previously sterilized by boiling. This is injected 
warm beneath the skin of the buttocks in cases of loss of blood 
or blood-poisoning; it has about the same osmotic pressure as 
the blood. 

On account of its cheapness sodium chlorid is the starting- 
point for obtaining sodium and its compounds, as potassium 
chlorid is, directly or indirectly, for that metal. 

Sodium bromid, NaBr, can be formed by saturating a solu- 
tion of the hydroxid with bromin. 

Sodium iodid, Nal, is prepared by a reaction like that used 
for potassium iodid. Essentially stated, ferrous iodid is acted upon 
by sodium hydroxid, leaving potassium iodid in solution and 
precipitating ferrous hydrate. 

The bromid and iodid resemble the chlorid in crystallizing in 
15 



226 THE METALS 

anhydrous cubes, but they are more soluble in water than is the 
chlorid. They are also soluble in alcohol. Dose: 5 to 60 gr. 

(Q-3-3-5 g m -)- # 

Sodium Nitrate (NaNO s ). — This corresponds to potassium 

nitrate, hence is called Chili niter, or saltpeter. It is found in a 
rainless district of Chili as solid deposits of colorless deliquescent 
crystals. It has a cool, bitter, saline taste with neutral reaction 
and is very soluble in water, but not in cold alcohol. It is the 
most important manure for cultivated plants. In dilute solution 
in the soil it is a valuable source of nitrogen for their nutrition. 
Dose: 8 to 40 gr. (0.5-2.5 gm.). 

Sodium Sulphate (Na 2 S0 4 , ioH 2 0) (Glauber's Salt).— This 
occurs dissolved in many saline aperient waters. In the manu- 
facture of nitric acid it is left in the retort: 

2 NaN0 3 + H 2 S0 4 = 2HNO3 + Na 2 S0 4 . 

Indeed, it is a product of the reaction that takes place on 
heating sulphuric acid with sodium salts of volatile acids gener- 
ally; thus in making hydrochloric acid from common salt: 

2 NaCl + H 2 S0 4 = 2HCI + Na 2 S0 4 . 

Properties. — It forms large, colorless prisms which effloresce 
in air, have a cool saline taste, and are neutral in reaction, very 
soluble in water, and insoluble in alcohol. It is an active purga- 
tive in the dose of 1 to 8 dr. (4-32 gm.). A teaspoonful in a 
large glass of water makes the intestinal contents thin and watery. 
The salt is not absorbed, so the osmotic pressure is high toward 
the intestines until their contents are of equal concentration with 
the body fluids. 

The solution of sodium sulphate stands for but two ions: 
sodion Na" and sulphanion (SOJ", which are present in great 
abundance. That the chemical activities are not due to sodium 
and anhydrous sulphuric acid is shown by the following facts: 
We have learned that it is difficult to keep the metal from passing 
into the condition of sodion. Notwithstanding this tendency, 
when sodium is absolutely dry it can be immersed in perfectly 
anhydrous sulphuric acid without any chemical change. This 
inertness disappears instantly on adding the least amount of 
water. The metal changes to the ion in the hydroxid Na'(HO)'. 
The water also gives hydrion H* to the sulphuric acid. Dissocia- 
tion produces sodion Na* and sulphanion (S0 4 )", the hydrion H* 
and hydroxidion (HO)' uniting and forming water which does not 
dissociate. 

2 Na', (HO)' + H',H-, (S0 4 )" = Na', Na*, (S0 4 )" + 2H 2 0. 



SODIUM 227 

Sodium bisulphate (HNaS0 4 ) {sodium acid sulphate) occurs 
in long four-sided crystals which decompose spontaneously into 
H 2 S0 4 and Na 2 S0 4 . 

Sodium Phosphates.— The theoretic relations of the three 
phosphates have been discussed under the head of Phosphoric 
Acid (p. 188). It remains to consider them practically. 

Sodium Normal Phosphate (Na 3 P0 4 , i2H 2 0) (Trisodium 
Phosphate, Basic Phosphate). — When sodium hydroxid is added 
to disodium phosphate, another atom of sodium is taken, forming 
a salt which crystallizes in six-sided prisms. It is freely soluble 
in water, with an alkaline reaction, absorbing water and carbon 
dioxid from the air to form Na 2 C0 3 and reverting to the more 
stable salt, HNa 2 P0 4 . 

Sodium Neutral Phosphate (HNa 2 P0 4 , i2H 2 0) (Sodium 
Orthophosphate, Disodium Phosphate). — This is prepared by the 
reaction between monocalcium phosphate and sodium carbonate: 

Ca(P0 4 H 2 ) 2 + 2Na 2 C0 3 = CaCO s + 2HNa 2 P0 4 + H 2 + C0 2 . 

It crystallizes in beautiful rhombic prisms which effloresce, 
losing 5H 2 0, hence it should be kept in well-stoppered bottles. 
It is very soluble in water, with a feeble alkaline reaction to lit- 
mus, but not to phenolphthalein (see p. 130). When a solution 
of the salt is saturated with carbon dioxid the liquid colors blue 
litmus red and red litmus blue, and it is said to have an ampho- 
teric reaction. Human milk and urine show this reaction not 
infrequently. It is present in the blood and other animal fluids. 
Under the name sodii phosphas (U. S. P.) it is used in medicine 
as a laxative and biliary stimulant. Dose: 1 to 8 dr. (4-32 gm.). 
Its incompatibles are lead acetate, carbolic acid, chloral hydrate, 
antipyrin, alkaloids, salicylic acid, and sodium salicylate. 

Liquor sodii phosphatis compositus is a concentrated solution 
of HNa 2 P0 4 with sodium nitrate and citric acid. Each cubic 
centimeter contains 1 gm. of the phosphate. Dose: J to 2 f. dr. 
(2-8 c.c). 

Sodium acid phosphate (H 2 NaP0 4 ) (monosodium phos- 
phate) is formed by treating disodium phosphate with phosphoric 
acid: 

Na 2 HP0 4 + H 3 P0 4 = 2NaH 2 P0 4 . 

It crystallizes in two forms and dissolves in water, forming an 
acid solution. It is present in the urine, imparting to that fluid 
an acid reaction (see p. 584). 

Sodium Carbonate (Na 2 C0 3 , ioH 2 0) (Normal Carbonate, 
Disodium Carbonate). — Under the name of sal soda or washing 
soda this is used as a domestic article to soften water and assist 



228 THE METALS 

in cleansing. It occurs in rhombic octahedrons or in large angular 
masses which effloresce and crumble to powder. It is alkaline, 
acrid in taste, soluble, and caustic in every respect, like the cor- 
responding salt of potassium, only less severe. 

Of the several methods of manufacture the Solvay ammonia 
process is the most economic. The reaction is between sodium 
chlorid and ammonium bicarbonate, the products being ammonium 
chlorid, which remains dissolved, and sodium bicarbonate, which 
is only sparingly soluble and therefore separates: 

NH 4 HC0 3 + NaCl = NH 4 C1 + HNaC0 3 . 

The bicarbonate, HNaCO s , when collected, dried, and heated, 
yields the carbonate, water, and carbon dioxid: 

2HNaCO s = Na 2 C0 3 + H 2 + C0 2 . 

The cryolite process is to heat that mineral, a double sodium 
and aluminium fluorid, with limestone: 

Al 2 Na 6 F 12 + 6CaCO s = 6CaF 2 + Na 6 Al 2 6 + 6C0 2 . 

Cryolite. Limestone. Calcium fluorid. Sodium aluminate. 

The sodium aluminate is dissolved out with water and treated 
with the C0 2 given off in the first stage: 

Na 6 Al 2 6 + 3 H 2 + 3C0 2 = 3 Na 2 C0 3 + 2 Al(OH) 3 

Sodium aluminate. Sodium carbonate. Aluminium hydrate. 

When the crystals of carbonate are heated they fall into a 
white powder of the monohydrated carbonate, sodii carbonas 
monohydratus (U. S. P.) Na 2 C0 3 .H 2 0. 

Sodium carbonate is a caustic alkali and, hence, is not given 
internally, unless in small doses of 5 to 10 gr. (0.32-0.65 gm.) 
largely diluted. The antidotes for it are the diluted acids, vinegar, 
lemon juice, and the oils with milk. 

Sodium bicarbonate (NaHC0 3 ) (acid carbonate, monoso- 
dium carbonate) occurs in Vichy and many other alkaline mineral 
waters. It can be made by the Solvay ammonia process given 
above, or by the action of carbon dioxid on the normal carbonate. 
Its crystals are without water and are permanent in the air. It is 
soluble in water, imparting a saline taste and an alkaline reaction. 
As carbonic acid is a very weak acid and its salts are hydrolyzed 
in solution, all soluble carbonates dissociate enough hydroxyl to 
give an alkaline reaction, the carbonic acid remaining almost 
undissociated: 

Na 2 C0 3 + H 2 = Na% (HC0 3 )' + Na", (HO/. 

NaHCO s + H 2 = Na', (OH/ + H 2 C0 3 . 



SODIUM 229 

If the monosodium carbonate is put in water and boiled, it loses 
C0 2 and dissolves as the disodium carbonate. If this is evapo- 
rated rapidly a salt separates, called the sesquicarbonate, 
Xa 4 H 2 (C0 3 \, sometimes written Xa 2 C0 3 , XaHC0 3 , 2H 2 0. 

Sodium bicarbonate is commonly called bread soda or cooking 
soda, to distinguish it from the other domestic salt, washing soda, 
from which it differs in the mildness of its local effects, being with- 
out caustic action. It is given internally in doses of 10 to 40 gr. 
(0.6-3 gm.) as an antacid. 

As it is harmless internally and is a convenient source of carbon 
dioxid gas. it is extensively used as a substitute for yeast in "baking 
powders" to "aerate" or "raise" bread. One kind of baking 
powder widely used is made by mixing a pound of potassium 
bitartrate with half a pound of sodium bicarbonate. A sufficient 
quantity is mixed with the dough, and in the process of baking 
the acid in the tartrate is neutralized by the sodium, and the gas 
COo. liberated in bubbles, disseminated through the bread, making 
it light and permeable by the digestive fluids. The reaction is: 

NaHC0 3 - HKC 4 H 4 6 = NaKC 4 H 4 O e + H 2 + C0 2 . 

Sodium Cream of 5c i:u-:-r ::.-55:un 

bicarbonate. tartar, tartrate. 

Another kind of baking powder which is considered hurtful 
because of the aluminium it contains is made by mixing common 
alum, or aluminium sulphate, with the sodium bicarbonate: 

6C(X 



6XaHC0 3 - A1 2 (S0 4 \ = 


= 3Xa 2 SO, + 2A1(H0) 3 


Sodium Aluminium 


Sodium Aluminium 


bicarbonate. sulphate. 


sulphate. hydrate. 



Sodium=potassium tartrate (XaKC 4 H 4 6 , 4H0O) {potassii 
et sodii tartras, U. S. P.), Rochelle salt) may be obtained in color- 
less crystals, though usually it is a white powder, of a bitter, saline 
taste, neutral in reaction, freely soluble in water. It is a mild 
laxative in doses of 4 to 8 dr. (8-32 gm.). 

Pulvis Effervescens Compositus (U. S. ?.) (Seidlitz Powder). 
— This is a preparation for administering Rochelle salt in an effer- 
vescing draught to conceal the bitter taste. One powder is in two 
papers, the blue and the white. The blue paper contains Rochelle 
salt, 2 dr., and sodium bicarbonate, 40 gr.; the white paper con- 
tains tartaric acid, 35 gr. If dissolved separately and the two 
solutions mixed there is brisk effervescence, due to the escape of 
the CO„. One or two of them may be taken while effervescing. 

Tests for Sodium. — (1) The most sensitive and readiest 
means of recognizing sodium is the bright-yellow color it imparts 
to the colorless flame of a Bunsen burner. The spectroscope 
places the sodium flame as an intense line in the pure yellow, cor- 



23O THE METALS 

responding to D in the solar spectrum. As all bright flames 
under ordinary circumstances show this D line, it is inferred that 
a trace of sodium is almost universal. Continued heat soon vol- 
atilizes this accidental trace of sodium on platinum wire. When 
the amount is appreciable by weight, say as much as 1 mg., the 
bright-yellow color lasts so much longer that the experienced 
analyst easily distinguishes it from the accidental trace (Fig. 19). 

(2) The salts of sodium are all white and are non-volatile to 
red heat. As they are all soluble in water, no ordinary reagent 
precipitates them. With the anions of hydrofluosilicic acid (SiF 6 )", 
and pyroantimonic acid (Sb 2 7 )", it forms compounds of low 
solubility. 

LITHIUM 

Symbol, Li. Atomic weight, 7. 

This metal occurs in combination in mineral waters and as a 
silicate in lepidolite. 

Properties. — Lithium resembles sodium in many respects, 
being silver white and ductile. With a specific gravity of 0.59 it 
is the lightest metal. It floats upon water, decomposing it, but 
not igniting the hydrogen. It burns at 200 C. (392 ° F.) with a 
crimson flame. Its compounds do not differ much from those of 
sodium. Its hydroxid reacts strongly alkaline. The salts used 
in medicine are the bromid and carbonate. 

Lithium bromid, LiBr, is obtained by saturating with lith- 
ium carbonate a solution of hydrobromic acid. It forms crystal- 
line needles that are very deliquescent and soluble in water and 
alcohol. Dose: 5 to 20 gr. (0.32-1.3 gm.). Its incompatibles 
are the acids; the salt of antimony, bismuth, silver, lead, mer- 
cury, copper; and the alkaloids. 

Lithium carbonate, Li 2 CO s , is a white alkaline powder, only 
sparingly soluble in water, but more soluble in carbonated water, 
which convert's it into the bicarbonate. Dose: 5 to 15 gr. (0.32-1 
gm.) ; 

Lithium citrate, made by the action of citric acid on the 
carbonate, is much more soluble than the carbonate. Dose: 5 
to 15 gr. (0.32-1 gm.). 

Lithii citras effervescens is a granular solid, containing 5.0 per 
cent, of the citrate mixed with enough sodium bicarbonate with 
tartaric and citric acids to react when dissolved, liberating carbon 
dioxid and forming neutral salts. 

Lithium urate is the compound made by the metal with 
uric acid of the body. It is more soluble than the natural urates, 
and hence lithium salts are given to dissolve urate deposits in the 
joints. 



AMMONIUM 23 1 

Tests for Lithium.— (1) Lithium is identified by the red 
color of its flame. The spectroscope shows two bright lines, one 
red and the other yellow, distinct from the sodium line (Fig. 19). 

(2) Concentrated solutions are precipitated by ammonium car- 
bonate as white lithium carbonate. 

RUBIDIUM 

Symbol, Rb. Atomic weight, 85.4. 

Although widely distributed in nature, the quantity of rubidium 
obtainable by convenient processes is very small. It gets its name 
from the two dark-red lines of its spectrum (Fig. 19). The metal 
and its compounds resemble potassium and its compounds very 
closely — physically, chemically, and medically. Its presence is 
doubtful if it cannot be identified by the color of its flame. It is 
separated from potassium by the fact that the double salt with 
platinum chlorid is a little less soluble than the corresponding 
potassium salt. 

CESIUM 

Symbol, Cs. Atomic weight, 133. 

This is an extremely rare metal, discovered by the two sky- 
blue lines of its spectrum (Fig. 19). It resembles rubidium and 
potassium, with more chemical energy than either, being the 
strongest base-former of all the elements. 

AMMONIUM 
Formula, NH 4 . Molecular weight, 18. 

A class of compounds closely resembling, physically and 
chemically, those of potassium has been found to contain the 
group NH 4 . When solutions of these salts are electrolyzed, the 
cation is (NH 4 )", and if mercury be used as a cathode, an amalgam 
is formed like that of potassium. Although the group has never 
been isolated as a metal, the ion is so much like the univalent 
cations of alkali salts that it is considered to belong to the same 
family with the alkali metals. 

Ammonia (NH 3 ) (Volatile Alkali). — This occurs in nature in 
small amounts widely distributed. A trace is present in the air 
and in surface waters that have been contaminated by nitrogenous 
waste. It is evolved from stable manure, and in the soil is most 
important as a source of nitrogen for the growth of plants. 

Preparation. — Ammonia can be formed by direct union of 
hydrogen and nitrogen, with the aid of the electric spark, by putre- 
faction or destructive distillation of proteid substances, and by 
heating ammonium hydroxid: NH 4 HO = NH 3 + H 2 0. The most 



232 



THE METALS 



convenient method is to heat an ammonium salt with a strong 
base, such as an alkaline hydroxid or lime: 

2 NH 4 C1 + Ca(HO) 2 = CaCl 2 + 2H 2 + 2 NH 3 

Ammonium chlorid. Calcium hydroxid. Calcium chlorid. Ammonia. 

Properties. — Ammonia, NH 3 , is a colorless gas having a 
pungent odor, irritating to the eyes and the mucous lining of the 
air-passages, and turning moist red litmus-paper blue. Under a 
pressure of 6J atmospheres at io° C. (50 ° F.) it is condensed 
to the liquid used in ice-machines to create a freezing temperature 
by its evaporation. Ammonium hydroxid is a strong solution of 
the gas in water. Water will absorb 700 times its volume at 
ordinary temperatures and thereby acquire the alkalinity, the 
pungency, and the chemical properties of the gas itself (Fig. 60). 
This is regarded as an act of chemical union in which the anhydrid 
NH 3 , unites with H 2 to form the hydroxid NH 4 HO. 

The liquefied ammonia gas, NH 3 , is used in ice-factories and 
refrigerators. Occasionally the receivers burst and the vapors fill 
the room, with deadly consequences to those who are exposed to 
them. To arouse fainting persons it is sometimes given too 
strong by inhalation. 

Ammonium Hydroxid (NH 4 HO) {Ammonia Water).— When 
ammonia is dissolved in water a compound is formed which 
neutralizes acids and forms salts; hence, it is basic. As the 
basicity is due to hydroxidio.n the dissociation of ammonium 
hydroxid is represented by the equation — 

NH 4 OH = (NH 4 )% (OH)'. 

The smell of the solution shows that some portion of the am- 
monia is still in the condition of the uncombined gas. The amount 
fj of hydroxyl dissociated is not so 

great as with potassium hydroxid 
n or sodium hydroxid, as is shown 

'■ " ~-— j| ^ th e l 0W er electric conductivity. 

In spite of the irritant action on the 
mucous membranes and the strong 
impression made on the olfactory 
nerves, ammonium hydroxid is not 
a strong base. Still, it readily forms 
salts with all acids. 

Under the names of hartshorn 
and ammonia, ammonium hydroxid 
is largely used in the household as a 

Fig. 6o.-Charging water with soluble gas. c l eans i ng age nt to remove paint, 

oil, and dirt generally from clothing; hence it is easy to have 
accidental poisoning with it. 




AMMONIUM 



2 33 



Pharmaceutic Preparations.— Aqua ammonia jortior (U. S. P.) 
contains 28 per cent, by weight of ammonia gas, has a specific 
gravity of 0.897, and is a powerful corrosive. It is incompatible 
with acids, alkaloids, chlorin water, iodin, bromin, and most 
metallic salts. Aqua ammonia (U. S. P.) has ij times more water, 
only 10 per cent, of ammonia gas, and a specific gravity of 0.958. 
Dose: 10 to 30 TTL (0.60-1.90 c.c). Spiritus ammonia (U. S. P.) is 
a solution of the gas in alcohol, of the same strength as the aqua, 
and better adapted for internal use. When it has added to it the 
carbonate, with small quantities of oils of nutmeg, lemon, and 
lavender, the aromatic spirits is produced. Dose: 1 to 2 fl. dr. 
(3.75-7.50 c.c). Ammonii carbonas occurs as whitish angular 
masses, giving off the characteristic irritating and alkaline vapor 
of ammonia, and caustic in strong solution (p. 235). 

Symptoms. — The nature and gravity of the effects will depend 
greatly on the strength of the solution, and on whether or not 
the subject received a strong dose of the vapor by the lungs. The 
direct chemical action upon vital tissue is the same as that of 
potassium hydroxid, though less in degree — that is, the albumin 
is dissolved, the fatty matter saponified, and the water abstracted. 
The respiratory symptoms are a suffocative feeling due to spasm 
of the glottis, followed by a sense of pain and weight in the chest, 
with an irritative cough due to inflammation of the larynx and 
trachea. 

The symptom due to the local caustic effect of the fluid is 
burning pain in the mouth and throat, extending to the stomach if 
the poison went so far. There are salivation, vomiting, and diffi- 
culty in swallowing. As a result of a free absorption of the poi- 
son by the lungs and stomach, cases display grave remote effects 
sometimes with great rapidity. The heart's action is sometimes 
arrested in a few minutes; sometimes there is immediate uncon- 
sciousness with coma, and death in a few minutes; sometimes 
there is unconscious delirium, soon ending in death. 

Fatal Dose. — A teaspoonful of the stronger aqua ammoniae 
has in at least one instance proved fatal, and two fluidrams have 
caused death in two or three other cases. Recovery, however, 
has sometimes followed much larger doses, such as a tablespoon- 
ful, and even upward of a fluidounce has been taken without 
fatal results. 

Fatal Period. — By suffocation and syncope death has occurred 
in four minutes after inhalation of the gas. On the other hand, 
death may occur after many months as a result of the starvation 
due to stricture of the gullet or pylorus. 

Treatment. — The antidotes are weak vinegar, lemon juice, 
oil, butter, and milk. The sequels are to be treated as they arise. 



234 THE METALS 

Postmortem Appearances.— These are not markedly different 
from the inflamed state of the alimentary tract as caused by the 
other caustic alkalis. When the vapor acts as an irritant upon 
the air-passages, an inflamed state of the larynx and even of the 
bronchi may be found. 

Ammonium chlorid (NH 4 C1) (sal ammoniac) is produced from 
the ammonia liquor of gas works by neutralizing with hydrochloric 
acid and evaporating. Although it forms a white crystal of the 
regular system it is usually found in tough fibrous masses, salty in 
taste, without odor and freely soluble. At 450 ° C. (862 ° F.) it 
passes into colorless vapors, which, if water be present, are a 
mixture of NH 3 and HC1. Although a neutral salt, the aqueous 
solution is feebly acid, owing to the slight hydrolysis to be expected 
with a salt of a weak base. Some ammonion unites with the 
hydroxidion of the water to form NH 4 OH: 

NH 4 C1 + H 2 = NH 4 OH + H% CI'. 

The weak ammonium hydroxid is dissociated to a much lower 
degree than is the strong acid hydrochloric. The excess of hy- 
drion causes the acid reaction. If the solution be boiled, a por- 
tion of ammonia escapes and the acid reaction increases. 

The facility with which it splits off hydrogen chlorid makes it 
useful as a flux to clean metallic surfaces for soldering and as an 
exciting salt in the Leclanche battery cell. Dose: 5 to 20 gr. 
(0.32-1.29 gm.) (p. 47). 

Ammonium nitrate, NH 4 N0 3 , can be obtained by neutral- 
izing nitric acid with ammonium hydroxid. The solution evap- 
orated yields long flexible prisms. Heated to 150 C. (302 °F.), 
the dry salt fuses, and at 210 C. (410 F. ) decomposes into nitrous 
oxid and water: 

NH 4 N0 3 = N 2 + 2 H 2 0. 

When quickly heated to a high temperature, it yields a large 
volume of mixed gases — ammonia, nitric, and nitrous oxids; 
hence, is used as an explosive. 

Ammonium acetate, NH 4 C 2 H 3 2 , is official in aqueous solution 
as liquor ammonii acetatis (U. S. P.) (spirit of mindererus), an anti- 
pyretic in doses of 2 to 8 f. dr. (7.4-30 c.c). This is a 7 per cent, 
solution of a salt made by saturating acetic acid with ammonium 
carbonate. 

Ammonium carbonate [(NH 4 ) 2 C0 3 ,H 2 0] (normal carbonate, 
diammonium carbonate) is formed as a white crystalline solid 
and is not stable. In air it breaks down rapidly into ammonia 
and a white powder of the acid carbonate: 

(NH 4 ) 2 C0 3 = NH 3 + NH 4 HC0 3 . 



AMMONIUM 235 

Ammonium bicarbonate (NH 4 HC0 3 ) (acid carbonate monoam- 
monium carbonate) is prepared by saturating ammonia water 
with carbon dioxid. It crystallizes in large rhombic prisms, 
stable, and freely soluble in water. Heated to 60 ° C. (140 ° F.) 
it breaks up into NH 3 + H 2 + C0 2 . 

Ammonium sesquicarbonate (ammonii carbonas, U. S. P., 
sal volatile, Preston salts) is a combination of the acid carbonate 
described above: NH 4 HC0 3 with a variable amount of salt of 
carbamic acid, called ammonium carbamate, NH 4 C0 2 NH 2 , which 
appears to be the carbonate deprived of water: 

(NH 4 ) 2 CO s — H 2 = NH 4 C0 2 NH 2 . 

The combined salts crystallize in hard translucent rhombic 
prisms with a pungent odor and an alkaline reaction. When this 
changes to the acid carbonate it may be used, in whole or in part, 
in place of sodium carbonate in baking powders. When used 
alone to aerate pastry, by the heat of the oven, it is all converted 
to H 2 and the gases NH 3 and C0 2 . Dose: 5 to 20 gr. (0.32- 
1.29 gm.). Its incompatibles are the acids, acid salts, alum, 
alkaloids, and most metallic salts. 

Ammonium Sulphid (NH 4 ) 2 S.— By saturating strong ammo- 
nium hydroxid with hydrogen sulphid in excess there is formed 
in solution ammonium hydrosulphid, NH 4 HS. To obtain ammo- 
nium sulphid, an equal volume of ammonium hydroxid must be 
added, so as to replace the second hydrogen atom. The solution 
containing (NH 4 ) 2 S is at first colorless, with a disagreeable odor, 
but soon turns yellow in the air from oxidation and separation 
of sulphur, part of which dissolves, forming polysulphids, and 
part is precipitated. It is used as a reagent to precipitate the 
heavy metals, the sulphids of which are soluble in free acids. It 
is also employed in organic chemistry as a reducing agent. The 
yellow sulphid is used to dissolve the sulphids of arsenic, anti- 
mony, and tin in analytic operations. 

Ammonium Phosphates. — There are three possible phos- 
phates, but the normal salt is too unstable to keep. The mono 
and diammonium phosphates exist, but are insignificant. 

Ammonium=sodium phosphate, (HNaNH 4 P0 4 , 4H 2 0), is 
called microcosmic salt because it is in the residue of evaporated 
stale urine of man, the microcosm. It is much used in blowpipe 
work to make a colorless bead on the platinum loop. Metallic 
compounds color the bead in characteristic tints. 

Tests for Ammonium Salts. — Ammonia gas turns red litmus- 
paper blue, and makes a white smoke when mixed with the fumes 
of a rod wet with hydrochloric acid. All salts are volatile when 
heated, and evolve the gas spontaneously or when heated with 



236 THE METALS 

calcium hydroxid. Platinum chlorid yields a yellow precipitate 
like that given by potassium. Not only does ammonium form 
salts, like those of potassium, of feeble solubility with the anion 
of chlorplatinic acid, but also with the anion of tartaric acid and 
the cobaltinitrite ion (p. 222). 

Detection of Ammonium Salts.— Owing to the volatility of 
ammonia, its hydroxid and its carbonate, these soon escape from 
the body. During life or soon after death detection is easy 
by the characteristic odor. If the volatile preparation has been 
fixed by the antidote, the vapor can be developed by heating 
the material with lime. This vapor will be alkaline and form 
white fumes with hydrochloric acid. 

If the organic material to be examined is putrid, allowance 
must be made for the ammonia produced by putrefaction. This 
is never enough to develop the dense white fumes of ammonium 
chlorid from a rod wet with hydrochloric acid. The amount 
may be estimated by distillation, neutralizing the distillate with 
hydrochloric acid, evaporating nearly to dryness, and precipitating 
the double chlorid of ammonium and platinum by adding excess 
of alcoholic solution of platinum chlorid. After filtration the 
precipitate is washed with alcohol, dried, and weighed; 100 parts 
represent 8.6 parts of ammonia, NH 3 . 

The Energy of Alkali Metals.— The chemical energy of all 
the members of this group is partly expressed in the statement 
that their ions are electropositive and univalent. Univalent 
metals carry but one electric charge, and, according to Faraday's 
law, the amounts of electricity set in motion are the same for each 
atom of an alkali metal. In the passage of free alkali metals to the 
ion state they take up equal quantities of electricity, as their capaci- 
ties are equal. Their differences of energy find an explanation in 
the other factor, the potential or intensity with which they work. 
The ions of potassium with a higher potential are discharged under 
certain conditions with greater readiness or velocity than those of 
sodium and ammonium. 



H— METALS OF THE ALKALINE EARTHS 

The alkaline earths — lime, CaO, baryta, BaO, strontia, SrO, 
and magnesia, MgO, are oxids with a reaction like the caustic 
alkalis, though they are much less soluble. The metals form 
divalent ions exclusively, are heavier than water, decompose water 
slowly, form normal carbonates and phosphates insoluble in water, 
but soluble when carbon dioxid is in solution, and form hydroxids 
that are sparingly soluble. 



CALCIUM 237 

CALCIUM 

Symbol, Ca. Atomic weight, 40.1. 

Occurrence. — In the form of silicates and carbonates this 
metal is very abundant and widely distributed in nature. Marble 
is the carbonate crystallized; limestone and chalk, the same salt 
less pure. It is also present in the shells of eggs and molluscs. 
Gypsum is the sulphate. The bones of animals are rich in the 
phosphate. 

Preparation. — Calcium is separated from the iodid by metallic 
sodium: 

Cal 2 + 2 Na = 2 NaI + Ca. 

When pure it is grayish-white, like polished iron, and fairly hard. 
Water attacks it slowly, and it unites with oxygen when heated. 

Calcium oxid (CaO) (Calx, Quicklime).— This is obtained 
by heating the carbonate, as limestone or marble, in limekilns: 

CaC0 3 = C0 2 + CaO. 

Carbonic acid is so weak that it cannot only be expelled by other 
acids, but even driven away as anhydrid by strong heat. 

Lime is a white, amorphous, almost infusible, powder. Exposed 
to the air it becomes air-slaked — that is, it absorbs moisture, forming 
hydroxid: 

CaO + H 2 = Ca(OH) 2 . 

At the same time the calcium hydroxid takes carbon dioxid to 
form calcium carbonate, so that it soon becomes chemically inert. 

Ca(OH) 2 + C0 2 = CaCO s + H 2 0. 

The absorption of C0 2 from the air to form CaCO a is practically 
a reversal of the reaction by which the C0 2 was driven off in 
lime burning. If that operation is carried on in a closed flask, 
we find that the temperature determines the result just as it 
determines whether water shall remain liquid or boil off in vapor. 
At ordinary temperature in the open there is more pressure of 
C0 2 in the atmosphere than the decomposition pressure of CaCO s ; 
hence the reaction is reversed and C0 2 is absorbed. 

The question of the degree of dampness in a room may be set- 
tled by closing it hermetically, weighing a dish, and putting on it 
1 kg. (2 lb.) of quicklime, and exposing it for twenty-four hours. 
If the kilogram gain in weight 1 gm., or the 2 lb. Troy gain 12 gr., 
then the room is too damp to be wholesome. 



238 THE METALS 

When lumps of quicklime are mixed with water, the water is 
absorbed, heat is evolved, the lime swells and breaks down into a 
white powder, which if added to more water remains for a time 
mechanically suspended as whitewash or milk oj lime. Eventually 
this settles and a very small percentage (0.14 per cent, or 1.4 gm. 
per L. — less than 1 gr. to 1 f. oz.) is left dissolved to make lime- 
water or liquor calcis (U. S. P.). Its electric conductivity shows 
that dissociation is almost complete. The following equation 
exhibits a relatively large amount of hydroxidion: 

Ca(OH) 2 = Ca", (OH)', (OH)'. 

These hydroxyl ions give it an alkaline reaction to litmus and 
confer upon it strong basic properties. Owing to its feeble sol- 
ubility there is very little concentration of these ions; hence, 
lime-water is used in the laboratory and medicine when very 
limited basic or antacid effects are desired. It is a clear, colorless, 
odorless liquid of feeble taste and sedative action. The milk of 
lime or lime paste is quite irritating to the stomach, acting like 
the caustic alkalis and sometimes causing dangerous inflammation, 
The antidotes are dilute vinegar, lemon juice, and the oils. Lime- 
water is kept standing over the excess of lime, so that it renews, 
its strength as fast as the surface layers take up carbon dioxid 
from the air to be precipitated as calcium carbonate. When th& 
gas is passed through lime-water, this salt separates and imparts, 
a milky appearance. Mortar and plaster are mixtures of sand, 
slaked lime, and water, which slowly change by exposure to air- 
to a hard mass of calcium carbonate and calcium silicate. In 
doing so they liberate water, making the wall damp for months, 
together, unless the process be hastened by open coal fires. 

Fresh milk of lime is used in chamber vessels to disinfect urine,, 
vomit, and feces. As whitewash, it disinfects the walls of cellars. 

Syrupus Calcis (U. S. P.) {Syrup oj Lime, Saccharated Solution 
oj Lime). — The solubility of lime is much increased by adding 
sugar. The amount dissolved is 7 or 8 gr. to 1 fl. oz. when 5 
per cent, of lime and 30 of sugar are boiled in 100 of water. The 
dose, as an antidote to oxalic and carbolic acids, is from \ to 2 dr. 
(1.95-7.80 gm.). Lime-water and the syrup are incompatible 
with acids and metallic salts generally. 

Linimentum calcis (U. S. P.) (carron oil) contains equal parts, 
of lime-water and linseed oil. It is a calcium soap. 

Soda lime is a mixture of quicklime and sodium hydroxid, dried. 
It is used in the laboratory for absorbing carbon dioxid from 
mixed gases. 

Calcium chlorid is used as a desiccating agent in the lab- 
oratory, in the form of a dried spongy mass. It is less perfect in 



CALCIUM 239 

this respect than sulphuric acid. In the anhydrous condition it is 
a colorless salt of great solubility. With water it forms five dif- 
ferent hydrates. The hexahydrate, CaCl 2 , 6H 2 0, occurs in large 
deliquescent crystals, which on heating lose water, becoming 
anhydrous. Dose as an antistrumous alterative: 5 to 20 gr. 
(0.32-1.2 gm.). 

Calcium Hypochlorite (CaOCl 2 ) (Calx Chlorinata, U. S. P., 
Bleaching Powder). — This substance has been fully considered 
under the head of hypochlorous acid (see p. 140). It does not 
contain calcium chlorid in the form of a mechanical mixture, as it 
does not deliquesce. When dissolved in water it dissociates in the 
same way as it would if there were calcium chlorid in it, though 

CI 
its composition is best expressed by the formula Ca< or • 

2Ca< oci = Ca "' cl2 ' + Ca " (ocl )' 2 - 

Calx Sulphurata (U. S. P.) Sulphurated Lime.— By heating 
together a mixture of calcium sulphate, starch, and charcoal, a 
compound is obtained which is misnamed calcium sulphid. It 
contains the sulphid CaS and also the sulphate CaS0 4 in varying 
proportions, not less than 36 per cent, of CaS. It is a grayish- 
white offensive powder with an alkaline reaction, slightly soluble 
in water, and used internally to combat suppuration. Dose: xV 
to J gr. (0.006-0.032 gm.). 

Calcium Carbid (CaC 2 ). — When carbon and lime are heated 
to the high temperature of an electric furnace they unite, carbon 
monoxid being set free: 

3C + CaO = CaC 2 + CO. 

While calcium carbid can be obtained pure as transparent crys- 
tals, the commercial product comes in grayish-brown hard lumps, 
with the odor of garlic or phosphureted hydrogen. Its value is 
due to the fact that it is decomposed by water with the formation 
of acetylene gas and calcium hydroxid : 

CaC 2 + 2 H 2 = C 2 H 2 + Ca(HO) 2 . 

The gas burns in air with a sooty flame which, when special 
burners are used to insure a larger proportion of oxygen, changes 
to an intensely white light. As acetylene is an explosive sub- 
stance, when mixed with air or oxygen, great care should be used 
with the apparatus for generating it on a large scale (p. S&t,). 
The brightness of the flame is due to the enormous energy 
absorbed from the electric furnace in the manufacture of CaC^ 



240 THE METALS 

and set free in the combustion of acetylene. It is 223 kilojoules 
more than that produced by burning the same amount of free 
C and H. The greater the heat, the brighter the light. 

Calcium Carbonate (CaC0 3 ).— The purest natural forms of 
this salt are Iceland spar, calc spar, or calcite, in rhombohedra; 
and arragonite, in rhombic prisms. Less pure, but still crystalline 
forms, are marble and limestone. Chalk is composed of minute 
grains of calcium carbonate. 

Creta Praeparata (U. S. P.) (Prepared Chalk).— The native 
chalk is freed from coarse mineral impurities by grinding it finely 
and suspending the finer particles in water, the coarser ones 
settling first. Prepared chalk is a white amorphous powder, 
without odor or taste, and insoluble in water. It is used as an 
astringent and antacid. Dose: 5 to 30 gr. (0.32-1.94 gm.). 

Mistura cretae (chalk mixture) is made by rubbing together 
chalk, sugar, gum, and cinnamon water. Dose: 4 f. dr. (7.39 c.c). 
Calcii carbonas praecipitatus, CaCO a , is made by mixing 
solutions of calcium chlorid and sodium carbonate: 

Na',Na- (C0 3 )" + Ca", CI', Cl', = Na-, Cl' + Na-,C1' + CaC0 3 . 

It is formed whenever calcion, Ca", meets carbanion, (C0 3 )", and 
is a fine, impalpable white powder, odorless and tasteless, insoluble 
in water, but soluble in water charged with carbon dioxid. 

Liquor Calcii Bicarbonatis (Calcium Bicarbonate). — The 
increased solubility of calcium carbonate in carbonic acid water is 
due to the formation of calcium bicarbonate, Ca(HC0 3 ) 2 . This 
salt has not been isolated, as evaporation leaves the original car- 
bonate, by loss of an equivalent of H 2 C0 3 . 

Ca(HC0 3 ) 2 = CaCO s + H 2 + C0 2 . 

This is a property that provides for an important movement 
of calcium in nature. Ground-waters charged with carbon dioxid 
are able to dissolve calcium carbonate from minerals and carry it 
to distant points to deposit it again when the gas evaporates. In 
this way are the stalactites of caves built up, layer on layer. In 
the ocean fishes and other marine animals get their calcareous 
skeletons from the calcium thus washed down by the rivers; in 
time their bones and shells make the chalk, limestone, and marble 
deposits. 

Waters charged with minerals are unsuitable for washing pur- 
poses because of their hardness. They form hard or insoluble 
salts with soap. By boiling, the water loses a portion of its hard- 
ness, owing to the escape of the carbon dioxid and the precipitation 



CALCIUM 241 

of the calcium carbonate. This lost part is said to be temporary, 
the remainder, due to other salts, is called permanent hardness. 
The crust in steam boilers is due to the solid residue of minerals 
left when the water has boiled off. 

Calcium sulphate, CaS0 4 .2H 2 0, occurs native in great abun- 
dance as gypsum and selenite. It is also found in natural waters 
in small quantities, as it takes 500 parts of water to dissolve it. 
When heated to 107 ° C. (225 ° F.) it loses three-fourths of the 
2H 2 it contains and is then known as plaster-oj-Paris, calcii 
sulphas exsiccatus (U. S. P.). The expulsion of part of its water 
has left the crystals as a white amorphous powder which takes 
up water again and solidifies in a few minutes as crystalline gypsum. 
It expands as it hardens and, therefore, makes a sharp cast of 
statuary and masonry decorations in relief. With it dentists 
make molds of the gums for shaping artificial teeth, surgeons 
apply it as a paste to bandages, which harden to immovable 
dressings. The finest plaster is used by dentists. This sets too 
quickly for the surgeon, who generally wants more time and who, 
therefore, chooses the medium grade. If common salt or alum be 
put in the water, the bandage dries more quickly. A mixture of 
dry calcium sulphate and common meal is used as a rat poison; 
after eating it and drinking water the plaster formed solidifies in 
the stomach. 

The calcium phosphates are three in number: the tertiary or 
normal, Ca 3 (POJ 2 ; the secondary, Ca 2 H 2 (P0 4 ) 2 ; and the primary 
or acid, CaH 4 (P0 4 ) 2 , called superphosphate. In these formulas, 
owing to the divalence of calcium, the formula of phosphoric acid 
is doubled thus: H 6 (POJ 2 , which permits of substitution of Ca" 
for two atoms of H. 

Tricalcium phosphate, Ca 3 (POJ 2 , is the normal or bone phos- 
phate. This is the most abundant mineral in the bodies of animals, 
giving solidity to the bones and supplying an essential principle 
to cell formation generally. In the soil it occurs in beds of phos- 
phate rock, consisting of the skeletons of minute organisms. 

Calcii phosphas prazcipitatus (U. S. P.) is prepared by calcining 
bones, dissolving the ash in hydrochloric acid, and precipitating 
with ammonium hydroxid. It is a white, tasteless, odorless pow- 
der, insoluble in water and in alcohol. Dose: 5 to 30 gr. (0.32- 
1.94 gm.). It is inert unless dissolved by the aid of some weak 
acid. 

Syrupus calcii lactophosphatis is a preparation in which it is 
made soluble by a little lactic and phosphoric acids, and pala- 
table by sugar and orange-flower water. Dose: 1 to 2 f. dr. (3.70- 
7.39 c.c). The solubility is due to a change of constitution: if a 
weak acid has been used, the secondary phosphate results; if a 
16 



242 THE METALS 

strong acid then the primary phosphate forms. Both are quite 
soluble in water* Thus, with a little hydrochloric acid, diluted: 

Ca 3 (P0 4 ) 2 + 2HCI = CaCl 2 + 2 (CaHP0 4 ) 

Tertiary phosphate. Secondary phosphate. 

By adding concentrated sulphuric acid to the bone phosphate, 
the primary or acid salt is formed: 

Ca 3 (POJ 2 J + 2 H 2 S0 4 = 2 CaS0 4 + CaH 4 (P0 4 ) 2 

Tricalcium phosphate. Monocalcium phosphate. 

Some calcium phosphate is indispensable to the growth of 
plants. Removal of crops impoverishes the soils to such an extent 
, that phosphatic fertilizers and animal manures must be used 
to restore their fundamental plant food. It is not easy for plants 
to absorb bone meal, though it is slowly dissolved in the soil. But 
the soluble acid phosphate under the name of superphosphate, 
restores to the soil in a highly assimilable form that which it had 
lost. 

Test for Calcium. — (1) In solution a calcium salt is pre- 
cipitated by a soluble carbonate, such as sodium or potassium 
carbonate, in the form of calcium carbonate. 

(2) Potassium oxalate or ammonium oxalate makes a white 
precipitate of calcium oxalate insoluble in acetic acid, but soluble 
in hydrochloric or nitric acids. 

(3) A concentrated solution of a calcium salt yields a white 
precipitate to sulphuric acid. 

(4) From concentrated calcium solutions the hydroxids of 
sodium or potassium precipitate white calcium hydroxid. Am- 
monium hydroxid does not precipitate calcium. 

(5) Its flame reaction is orange-red in color. The spectrum 
shows lines in the orange-red, green, and blue. 

MAGNESIUM 

Symbol, Mg. Atomic weight, 24. 

Occurrence. — This metal is found in considerable quantities, 
widely distributed, in nature in the minerals: magnesite, sl carbo- 
nate; dolomite, a mixed carbonate of calcium and magnesium; 
kainite, a double sulphate of magnesium and potassium and 
various silicates, such as soapstone, asbestos, mica, serpentin, meer- 
schaum, and hornblende, capable of standing high temperatures. 

Preparation. — Large amounts are now separated by electro- 
lysis of fused carnallite, which contains magnesium chlorid. 

Properties. — Magnesium is a white, tough metal, which 
remains untarnished in dry air for a long time, but in boiling 



MAGNESIUM 243 

water it slowly evolves hydrogen. It dissolves readily in dilute 
acids, evolving hydrogen. It burns in air with an intense white 
flame, useful in photographing. To make a flash-light the pow- 
der may be blown through a flame or ignited in a mixture with 
potassium chlorate. The strong light is due to the fact that in 
spite of the great heat of its combustion the oxid produced is 
neither melted nor vaporized, but glows as incandescent solid par- 
ticles. 

The position assigned to sodium in the potassium family 
belongs to magnesium in the calcium group. It is found in more 
natural compounds than calcium, and differs from it more than 
calcium does from strontium and barium. The taste of all its 
soluble salts shows that its ion is bitter. 

Magnesium Hydroxid, Mg(HO) 2 .— When a solution of magne- 
sium sulphate or chlorid is treated with excess of sodium or potas- 
sium hydroxid, a white gelatinous precipitate separates. A trace of 
it dissolves and turns red litmus blue. In solution of ammonium 
chlorid or other ammonium salt the magnesia dissolves. The 
dry Mg(HO) 2 is a white powder which, on being heated, loses 
water, changing to magnesium oxid. 

Magnesium Oxid, MgO (Magnesia).— This is best prepared 
by heating the light carbonate. A white, fine, bulky, and light 
powder is produced, called calcined magnesia. It is tasteless, 
odorless, and, though almost insoluble in water, it still turns 
moist litmus-paper blue. On standing with 15 parts of water for 
half an hour it becomes hydrated to a gelatinous magma. It is 
used as an antacid and antidote. Dose: 5 to 60 gr. (0.32—3.88 
gm.). It is a component of Jerri hydroxidum cum magnesii oxido, 
the antidote for arsenic. 

Magnesii Oxidum Ponderosum. — Heavy magnesia is made 
by calcining the heavier variety of carbonate. It is a white, fine, 
dense powder which does not gelatinize in water and is slower 
in action than light magnesia, though it corresponds to it in other 
respects. The dose is the same. 

Magnesium chlorid, MgCl 2 , is a deliquescent salt formed 
by the action of hydrochloric acid on the oxid or carbonate. It 
is present in various bitter, saline mineral waters, to which it 
imparts a laxative property. 

Magnesium carbonate, MgC0 3 (normal or neutral carbonate), 
is formed by passing carbon dioxid through a mixture of water 
and the basic carbonate. 

Magnesii Carbonas (U. S. P. ) (MgC0 3 ) 4 , Mg(HO) 2 . 5H 2 0.— 
When a solution of magnesium sulphate or chlorid is treated 
with one of sodium carbonate, C0 2 is evolved and a white gelat- 
inous precipitate forms, which is a varying mixture of carbonate 



244 THE PETALS 

and hydroxid. 1 If the solution be dilute and cold, very little 
CO z is evolved. The deposit is white, light, and bulky, and is 
called magnesii carbonas levis, or magnesia alba. It is mostly 
Mg(HC0 3 ) 2 , the bicarbonate. If the solution used be concen- 
trated and hot, and the water be boiled off, a denser product is 
obtained, containing some hydroxid, and called magnesii car- 
bonas ponderosus. This is sometimes dispensed in large cubes. 
Both forms are white, light, faintly earthy in taste, and insoluble 
in water. They neutralize the acids of indigestion and the cor- 
rosive acid poisons. 

Magnesii bicarbonas (fluid magnesia) is a solution of the 
carbonate in water charged with carbon dioxid. It is alkaline 
and bitter in taste. 

Mistura magnesias et asafoetidae (Dewees 1 carminative) con- 
tains the carbonate, tincture asafetida, tincture opium, sugar, and 
water. It is given for flatulent diarrhea. Dose: i to 4 fl. dr. (3.75- 
15.00 c.c). 

Magnesium sulphate, MgS0 4 -7H 2 (Epsom salt), occurs in 
sea-waters and in waters of bitter saline mineral springs. The 
salt is prepared by the action of sulphuric acid on magnesium 
carbonate, prismatic or acicular crystals forming, which are 
freely soluble and neutral, with a cool bitter taste. It is a favor- 
ite cathartic when free watery discharges are desired. The purged 
fluid flows from the vessels into the intestines by osmotic pressure. 
To mask the bitter taste possessed by the soluble magnesium salts, 
effervescing solutions are used, in which carbon dioxid is liberated 
from a carbonate by the action of citric acid. 

Magnesii sulphas ejfervescens is a granular mixture of magnesium 
sulphate and sodium bicarbonate with tartaric and citric acids. 
Dissolved in sweetened water the C0 2 set free marks the bitter 
taste of the sulphate. 

Liquor Magnesii Citratis (Effervescing Citrate of Magnesia).— 
This is a palatable solution, quickly mixed and tightly stoppered 
so as to retain the carbon dioxid. It contains magnesium car- 
bonate, citric acid, syrup, potassium bicarbonate, and water. 
Dose as a cathartic: 2 to 8 fl. oz. (60-236 c.c). 

Detection of Magnesia.— The ion magnesium is divalent 
and colorless, like that of calcium. Its carbonate, like that of 
other alkaline earths, is insoluble in water, but unlike the others, 
soluble in ammonium salts like the chlorid. Hence, to separate 
it from them, ammonium chlorid is added to the suspected solu- 
tion until it ceases to precipitate with ammonium hydroxid. 

1 In another place (p. 228) it has been stated that the alkaline carbonates are 
split by solution in water forming some hydroxid which turns red litmus blue. 
Magnesion, Mg", is thrown down by both the anions (C0 3 )' and (HO)' thus formed 
by hydrolysis. 



BARIUM 



2 45 



If now ammonium carbonate be added, carbonates of calcium, 
strontium, and barium are precipitated, leaving magnesium in 
solution. After nitration a solution of disodium phosphate is 
added to the nitrate. There being ammonia present already, 
there is deposited a crystalline precipitate of ammonium mag- 
nesium phosphate, MgXH 4 P0 4 . All the heavy metals must 
have been separated first by hydrogen sulphid or ammonium 
sulphid. There is no characteristic color to the magnesium 
flame. 

STRONTIUM 
Symbol, Sr. Atomic weight, 87.68. 

This metal and barium are more closely allied to calcium than 
is magnesium, just as cesium and rubidium resemble potassium 
more than does sodium. They are much rarer than calcium and 
magnesium and have little medical interest, though barium figures 
as a poison because of its employment in pyrotechnics. Strontium 
is found in nature combined in its sulphate, celestite, and in its 
carbonate, strontianite. The metal is obtained readily by electro- 
lysis of its fused chlorid. It is yellowish, rather tough, like cal- 
cium, unites with oxygen in the air, and reacts energetically with 
water, evolving hydrogen. Its ion, Sr", is divalent and behaves 
so much like calcion, Ca", that it is worth while to consider its 
salts in detail. The bromid, iodid, and salicylate are official and 
are used in medicine with essentially the same indications as the 
corresponding salts of potassium. The chief use is in the making 
of fireworks, growing out of the beautiful dark-red color of its 
flame. Its detection depends on the fact that it is the common 
substance that gives this flame reaction. The spectrum shows 
lines in the red, orange-red, and blue. 

BARIUM 

Symbol, Ba. Atomic weight, 137. 

Occurrence. — This metal occurs in nature as the sulphate, 
barite, and as the carbonate, wither ite. It is obtained by passing 
the electric current through the fused chlorid. 

Properties. — It is a white metal resembling calcium and 
strontium in that it oxidizes in the air and reacts energetically 
with water. Its ion Ba", is divalent, colorless, and poisonous. 
It is recognized by the heavy white precipitate with sulphuric acid 
and the sulphates, and by the yellowish-green color of its flame. 

The hydroxid, Ba(HO) 2 , or baryta water, is more soluble and 
more basic than lime-water, and is used to neutralize acids and 
test for carbon dioxid. 

Ba(OH) 2 + C0 2 = BaCO.3 + H 2 0. 

Barium hydroxid. Barium carbonate. 



246 THE METALS 

The soluble salts, barium nitrate, Ba(N0 3 ) 2 , and barium chlorid, 
BaCl 2 , are used as reagents for precipitating sulphanion, SO/', in 
barium sulphate, the most insoluble of sulphates and of barium 
salts: 

Ba", (N0 3 )', (N0 3 )' + K-, K% (S0 4 )" = 2K-, (NO s )' + BaS0 4 . 

As fast as barion is neutralized by the union with the sulphan- 
ion, BaS0 4 is precipitated, insoluble, and therefore undissociated. 
Because of its resistance to acids and solvents it wears well as a 
pigment under the name " permanent white." 

Certain salts of barium used in pyrotechny, in wood-staining, 
and in glass-making sometimes figure in toxicology as irritant 
poisons which, when absorbed, cause cardiac depression and con- 
vulsions. The chlorid and the nitrate occur in white, soluble 
crystals resembling the ordinary purgative "salts," for which 
they have been taken by mistake. 

Symptoms. — Gastro-intestinal irritation is shown by vomiting 
and diarrhea, with straining and abdominal pain. After absorp- 
tion dilation of the pupils with convulsions, paralysis, and heart 
failure may supervene. 

Fatal Dose. — About 100 gr. (6.5 gm.) of the chlorid proved 
fatal to a woman, although by gradually increasing the daily 
quantity, Pivondi was enabled to take in divided doses 119 gr. 
(7.7 gm.) in a day. 

Fatal Period. — Death occurred in one case in one hour, in 
another case in fifteen hours, in another case in thirty-four hours, 
and again as late as a week after taking the poison. 

Treatment. — The best chemical antidote is magnesium sul- 
phate (Epsom salts) or sodium sulphate (Glauber's salts). Both 
have the power to precipitate the barium as insoluble sulphate. 
The stomach should then be washed out with milk and water. 
Anodynes are indicated for pain; heat and stimulants for the 
cardiac depression. 

Postmortem Appearances.— Any or all of the signs of gastro- 
intestinal inflammation may be present — i. e., patches of redness, 
swelling, softening, effusions, ulcerations, and even perforation. 

Experiments on rabbits show that after chronic poisoning for 
thirty days all the organs contain barium — the bones most of all, 
the kidneys, brain, and spinal cord show a less amount, the liver 
still less, and traces only are in the lungs, heart, and muscles. 

Tests. — 1. Dilute sulphuric acid precipitates barium sulphate, 
which is insoluble in hydrochloric or nitric acid. 

2. Neutral potassium chr ornate gives a yellow precipitate, 
insoluble in water, but soluble in hydrochloric or nitric acid. 



RADIUM 247 

3. A green hue is given to a colorless flame when a barium 
salt is held in it by a loop of platinum -wire moistened with hydro- 
chloric acid. 

Detection. — Having dissolved the organic matter by hydro- 
chloric acid and potassium chlorate and precipitated most of the 
common metals by hydrogen sulphid and ammonium sulphid, 
the filtrate is treated with ammonium carbonate, which precipitates 
barium, strontium, and calcium carbonates. This precipitate is 
dissolved in nitric acid and dried until the free acid is driven off. 
The residue is treated with equal parts of absolute alcohol and 
ether, which dissolve calcium nitrate, but leave the others undis- 
solved. The calcium solution gives a white precipitate to sul- 
phuric acid. The residue, dissolved in water and treated with a 
little acetic acid and potassium chromate, gives a yellow precipitate 
of barium chromate. The filtrate, treated with ammonium car- 
bonate and ammonia, gives a white precipitate of strontium carbo- 
nate. 

By another method the organic matter may be burnt, the ash 
fused with sodium carbonate, dissolved in hydrochloric acid, and 
tested as stated above. 

RADIUM 

Symbol, Rd. Atomic weight, 223. 

This is a hypothetic metal of the alkaline earths, closely related 
to barium. 

Occurrence. — Radium is found in excessively minute quan- 
tities in pitchblende, a black mineral found in Colorado, Texas, and 
Bohemia; the mineral is rich in uranium oxid. 

Preparation. — By tedious and difficult processes of fractional 
crystallization a ton of pitchblende will yield 1^ gr. (0.1 gm.) of 
radium chlorid with some barium, from which latter it is not 
possible to separate it completely. The metal itself has not been 
isolated. In the free state it would quickly oxidize, but as chlorid 
or bromid it forms permanent salts. 

Physical Properties. — Radium chlorid is obtained as small, 
colorless, self-luminous crystals. It burns with a brilliant red 
light, which gives a characteristic spectrum of vivid lines. From 
its properties an atomic weight has been deduced of 223. This 
is the highest of any known substance; the two elements nearest 
to it in weight, uranium and thorium, have the same remarkable 
property of radio-activity. 

Radio-activity is a property first discovered by Becquerel in 
the uranium salts obtained from pitchblende. They emit spon- 
taneously invisible radiations, which penetrate opaque substances 
and show their presence by blackening sensitive photograph 



248 THE METALS 

films and by conducting away, through the air, the charge of 
electrified bodies. The rays from the electrified current stream- 
ing from the cathode of a Crookes vacuum tube, and the Ront- 
gen rays given off from the glass of that tube when bombarded 
by the radiant matter, have these properties; but the rays emitted 
by uranium, thorium, and radium are produced incessantly and 
irresistibly without the outside stimulus of electric excitement. 
Radium has radio-activity intensified 2,000,000 times beyond the 
standard fixed by uranium. The radium emission like that of the 
Crookes tube, is sufficiently intense to produce fluorescence in 
barium platinocyanid, which is not the case with the rays from 
uranium and thorium. 

The intensity of this radiating action is measured definitely by 
the rate of leakage of electricity in a certain period, from a charged 
electrometer, due to the increased conductivity of a given quantity 
of air caused by the "ionizing" influence of the emitted rays. 
The unit of intensity is the radio-activity of uranium. Thus, 
when it is said that a sample of radium salt has a radio-activity 
of 5000, it is meant that the rays emitted by the sample raise the 
conductivity of the air 5000 times as much as would an equal 
weight of uranium. 

Radium emits three kinds of rays and a radio-active gaseous 
emanation. The three rays are named a (alpha) or ionic, ft (beta) 
or cathodic, and y (gamma) or (Ethereal, like the Rontgen rays. 

The alpha species consist of particles or ions of twice the mass 
of hydrogen atoms; they are charged positively, are projected 
with a velocity of about 20,000 miles per second, can be deflected 
by a magnet, are readily absorbed by surrounding objects, have 
little penetrative power, and ionize gases so that electrified bodies 
near by are rapidly discharged. 

The beta species are flying corpuscles or electrons, one thou- 
sandth the weight of a hydrogen atom; they are negatively charged, 
strongly affect the silver salts of a photographic plate, traverse 
glass and many opaque solid partitions, and are influenced by 
a magnet. 

The gamma species, like waves in the aether, move in straight 
paths, are neutral electrically, are not deflected by a magnet, and 
penetrate most substances, even thin plates of lead. 

The gamma rays are considered to be identical with the irregular 
and intense pulses of the Rontgen rays emitted from the high 
vacuum Crookes' tube when excited by electricity. 

The emanation is not projected at a high speed, but wells 
forth as a luminous gas, slowly, without ceasing, imparting feeble 
luminosity to any body it may touch. In a dark room it can be 
seen, by its luminosity, to be subject to draughts, to flow inside 



RADIUM 249 

glass tubes, to penetrate cotton-wool, sulphuric acid, and thin 
metallic foil, but to be stopped by mica. It is unaffected by all 
chemical reagents, but is condensed by low temperatures. Its 
boiling-point is — 150 C. ( — 238 F.). It imparts temporary 
radio-activity to surrounding objects, apparently by a deposit of 
invisible powder so minute that in years the accumulation would 
not be weighable. Neutral electrically, it can ionize other gases 
so as to disperse electric charges. Even when confined with the 
utmost care, in a month it disappears entirely, no matter if it be 
hermetically sealed. The colored bands characteristic of the 
emanation spectrum are seen in a few days to show the yellow- 
green line typical of helium, and eventually the lines are those 
of helium throughout. If the emanation be dissolved in water 
it generates the gas neon, if dissolved in a solution of copper 
sulphate it generates argon and lithium with perhaps sodium and 
calcium. 

Heat Radiation. — Pure radium chlorid, without cessation and 
for an indefinite period, evolves heat enough to maintain itself at 
a constant temperature of 1.5 ° C. (2.7 ° F.) above other objects in 
the room. A gram weight gives off 100 calories every hour, an 
amount sufficient to raise 1 gm. of ice-water to the boiling-point. 
In a year the amount of energy put forth is enormous, and yet 
the loss of weight is so infinitesimal that the most delicate balance 
will not indicate it. 

Transmutation. — The rate of emission is unlike that of a 
chemical process in that it is unaltered by change of temperature. 
Even the cooling by immersion in frozen hydrogen has no effect. 
All the elements whose atomic weight exceeds that of Bi. 208 appear 
to be undergoing spontaneous dissociation with liberation of heat 
a million times as much as that of their combustion or of any 
other chemical process known. This decomposition appears to 
consist in separating helium, atomic weight 4, leaving an element 
whose atomic weight is 4 or a multiple of 4 less than that of the 
element first taken; thus it is probable that uranium casts off 
helium, leaving thorium as if it were ThHe 2 ; later thorium dis- 
aggregates to radium and helium as if it were RdHe,; and 
radium itself disengages helium, the series of changes probably 
ending in the production of lead with atomic weight 206.9 as if 
radium were Pb.He 5 . 

Induced Radio-activity. — If a sealed tube containing radium 
be immersed for a day in normal salt solution and then removed, 
the solution for a few days shows all the radio-active powers, 
though in a lower degree, which diminishes rapidly. 

Chemical Properties. — The emitted rays convert oxygen 
into ozone and change yellow phosphorus to red. The alplia 



250 THE METALS 

rays immediately coagulate a sensitive solution of globulin. The 
beta and gamma rays liberate iodin from iodoform in the presence 
of oxygen. 

Physiologic Effects. — Under the influence of the rays, 
nutrition is profoundly modified, the development of growing 
animals arrested, and after prolonged exposure some are killed. 
Radium chlorid, when uncovered at a short distance, soon in- 
flames the skin, producing painless ulcers; the partially blind 
are enabled to see luminous appearances, and by its injurious 
effects upon the nervous system it induces paralysis and death. 
Cautiously applied directly to the part, it is used to break up 
superficial cancers and growths, like lupus, rodent ulcer, and 
the hypertrophied thyroid of goiter. For this purpose at least 
1 mg. of 1,000,000 activity is required. As it destroys bacteria, 
it has been hoped that inhalation of the emanation or some radio- 
active vapor will prove helpful in tuberculosis of the lung. As 
yet no such specific curative power has been proven. 

Subatomic Matter.— Viewed in the light of recent discov- 
eries, the picture of the constitution of substances — the atomic 
theory — has its details somewhat blurred, though not blotted out, 
nor is the outline effaced. The notion that matter is granular 
or atomic still subsists, as it rests upon the necessity of chemistry 
for separate combining units which are centers of force. But 
the physical integrity of the chemical atom can no longer be main- 
tained. Through the highly exhausted vacuum of a Crookes 
tube negative electricity streams in electrons of radiant matter, 
which are neither molecules nor atoms. These cathode rays are 
convection currents of electricity, like the stream of ions in liquid 
electrolytes, but differ from them in having carriers 1000 times 
less massive than the hydrogen atom. "The negatively electrified 
particles have the same charge and the same mass, whatever be 
the nature of the gas in the tube or the nature of the electrode. 
They therefore form an invariable constituent of the atoms and 
molecules of all gases, and presumably of all liquids and solids" 
(Thomson). 

The electron theory assumes that electric conduction is the 
property of subatomic units of negative electricity which are de- 
tached from the atoms. The atom may be considered as an open 
structure with vacant spaces relatively large and a cluster of these 
much smaller electrons in violent motion within the relatively 
enormous atomic space, controlled by electric forces which nor- 
mally in the aggregate are neutral. The chemical characteristics 
of the atom are due to its mass, which is proportional to the number 
of its electrons. The ions of solutions are atoms carrying more or 
less of these electrons than belong to them in their normal or 



ALUMINIUM 251 

neutral state. If more, they are positive, if less negative. 
When a molecule of NaCl dissociates, the Na" atom receives an 
electron from the CI' and their neutrality is lost. Valency is 
electric in character. The electropositive univalent atom, such 
as hydrogen, engaged in a chemical action reaches equilibrium 
on losing one electron. The electronegative univalent atom, 
such as chlorin, becomes stable when it gains one electron. The 
divalent positive oxygen atom becomes stable by losing two elec- 
trons, and so on. Valency on this hypothesis is an effect of the 
number of electrons that can get free from or are caught up by 
the aggregation of electrons which constitute the particular kind 
of atom. Radio-activity is an effect of perturbations of the 
subatomic forces and a subversion of the normal system, which 
is attended by the loss of energy emitted in rays, the disintegration 
of the atom, and such transmutations of substances as are seen 
in the radium emanations (p. 248). 

Radio=activity Common. — Many ordinary things are found to 
be radio-active in an exceedingly minute degree, such as ground 
air from cellars and caves and newly fallen snow and rain, surface 
waters and that of mineral springs, tinfoil, glass, silver, lead, 
copper, zinc, aluminium, platinum. But marked radio-activity 
is a property of the elements of heavy atomic weight only. 



IE.— THE EARTH METALS 

ALUMINIUM 
Symbol, Al. Atomic weight, 27. 

Occurrence. — This is the only element belonging to the 
group of metals of the earths which is at all common or which 
has any practical value. It ranks next to oxygen and silicon in 
abundance and is of great importance, whereas the others are 
exceedingly rare and of little interest. The members of this 
group, aluminium, scandium, yttrium, lanthanum, gallium, ytter- 
bium, etc., all form trivalent ions. Aluminium silicate is not only 
a constituent of many crystalline rocks, but is also the chief com- 
ponent of clays and slates. Nearly all minerals, except sandstone 
and limestone, are ore beds of it. Every brick has nearly a 
pound of this metal in it. A native aluminium silicate is official 
under the name of kaolinum. It is a soft, white powder, clay-like 
in taste, insoluble in water. It is used in making pill masses 
and also in the cataplasma kaolini, U. S. P., which contains 
kaolin, boric acid, thymol, methyl salicylate, oil of peppermint, and 
glycerin. It is used as an antiseptic, hygroscopic, plastic dressing. 



252 THE METALS 

Preparation. — Aluminium oxid is fused in iron crucibles by 
the heat of the electric current, which then decomposes it, the 
metal seeking the cathode container, and the oxygen uniting with 
the carbon anode to form carbon monoxid. To obtain fusion at a 
lower temperature cryolite, a double fluorid of aluminium and 
sodium, is first melted as a bath in which the oxid fuses and breaks 
up and the used-up oxid of aluminium is replaced as the process 
requires. 

Properties. — Aluminium is a bluish-white, silvery metal,, 
changing very little on exposure to the air. It is protected from 
deep rust by an imperceptibly thin film of oxid, which quickly 
forms and firmly adheres. It can be drawn into hair-like wire 
and beaten into very thin leaf for " silvering." As it does not 
blacken, like silver, and is extremely light (specific gravity 2.7), 
it is often used for household ware. Melting at 700 ° C. (1292 
F.), it is easily molded. It is a good conductor of heat and elec- 
tricity. Its drawbacks are its softness, its inability to resist the 
action of salt solutions, and its solubility in alkalis. At high 
temperatures it combines with oxygen, giving a brilliant light 
and great heat. Two alloys of great stability are in use: alu- 
minium bronze, which is golden yellow, and magnalium, white;, 
the latter contains about 20 per cent, of magnesium 

It is attacked and dissolved by acids: 

Al + 3HCI = AICI3 + 3H. 

The ion of aluminium is trivalent, Al'", and colorless, forming 
salts which are astringent and soluble. These salts when dissolved 
resemble the alkaline carbonates in that they are split up by 
water into the hydroxid and acid. The hydroxid being a weak 
base, the hydrion of the strong acid makes the reaction acid, thus: 

AICI3 + 3 H 2 = Al(OH) 8 + 3HCI. 

The proof of this dissociation of A1C1 3 is found in the fact that 
the original salt is not obtained when the water is evaporated. 

Aluminium hydroxid, Al(OH) 3 , hydrated alumina, is formed 
as a gelatinous precipitate from solution of aluminium salts on 
the addition of a small quantity of an alkali or alkaline carbonate. 

A1 2 (S0 4 ) 3 + 6NH 4 OH = 3 (NH 4 ) 2 S0 4 + 2 Al(OH) 3 . 

If the liquid contain suspended particles or coloring-matter, 
these are carried down, and give a color to the dried precipitate, 
which, under the term lake, is used as a pigment. Aluminii hydrox- 
idum (U. S. P.) is a light, white, amorphous powder, without. 



ALUMINIUM 253 

taste, wholly insoluble in water or alcohol, but soluble in strong 
acids or alkaline solutions. Dose: 3 to 15 gr. (0.2-1.0 gm.). 
When heated to redness the hydroxid changes to oxid: 

2Al(OH) 3 = A1 2 3 + 3 H 2 0. 

The hydroxid is weakly basic, forming with acids three kinds 
of salts, according as one, two, or three hydroxy 1 groups are 
replaced by the acid ions. Although precipitated by caustic 
potash or soda in small amounts, the precipitate dissolves in 
excess of these alkalis, forming soluble aluminates. Metallic 
aluminium dissolves in the caustic potash or soda, with the for- 
mation of aluminate and the evolution of hydrogen: 

3KHO + Al = K3AIO3 + 3H. 

This reaction shows that its hydroxid, x\10 3 H 3 , acts in this case 
as an acid, splitting off acid hydrogen from its hydroxyl groups. 
Like a tribasic acid, it yields three anions, (H 2 A10 3 )', (HA10 3 )", 
and AlOg/". Neither the acid nor basic quality can be strong 
in a substance which plays either part according to circumstances. 
Much concentration of the acid-hydrogen ion and the basic- 
hydroxyl ion would cause the formation of undissociated water, 
as when a strong base and acid meet. Unlike the magnesium 
salts, aluminium hydroxid is not soluble in excess of ammonia. 
The absence of solvent power is due to the weak basicity of 
ammonia. 

Aluminium hydroxid is so weakly basic that it does not take 
carbonic acid from the air or water. No carbonate is ever formed, 
but the silicate is carried suspended as a fine powder by rivers 
and deposited in quiet waters as clay. 

Aluminium oxid, A1 2 3 , alumina, occurs nearly pure in nature 
as a hard mineral corundum. Sapphire is a blue and ruby is a 
red variety, colored by admixture of cobalt or chromium. When 
obtained by calcining the hydroxid it is a light, white, odorless 
powder, which fuses at a high heat and forms hard crystals on 
cooling. A hard granular variety, colored dark by iron oxid, is 
known as emery. 

Aluminium chlorid, A1C1 3 , is prepared by the action of 
hydrochloric acid on aluminium hydroxid. It is a very hygro- 
scopic, white crystal, used in organic chemistry with mixtures of 
a hydrogen compound and a chlorin compound, to promote the 
union of the hydrogen of one with the chlorin of the other, and 
causing the residues to combine in a synthetic compound. 

Aluminium sulphate, A1,(S0 4 ) 3 + i8H 2 0, is prepared by 
heating aluminium silicate or aluminium hydroxid with sulphuric 



254 THE METALS 

acid. It is a white crystalline powder, freely soluble in water 
and insoluble in alcohol. It is used in medicine as a local as- 
tringent. Owing to the weakness of aluminium hydroxid as a 
base, this, like the other salts, is hydrolyzed by water, so that an 
appreciable per cent, of hydrion causes it to react acid. This 
salt is used as the acid factor in some baking powders (see p. 
229). It does not crystallize so well as alum, but by using pure 
materials in its manufacture better results are obtained than for- 
merly. 

Alum (Alumen, U. S. P.). — This name was first applied to the 
double sulphate of aluminium and potassium, A1K(S0 4 ) 2 , i2H 2 0. 
Mixed in the right proportions, solutions of potassium sulphate 
and aluminium sulphate will form beautiful regular octahedra 
with a sweetish astringent taste and acid reaction. It is soluble 
in water, but insoluble in alcohol. Dose: 10 to 15 gr. (0.66-1.00 
gm.). 

Common alum is a type of a large series of isomorphous salts,, 
which are double sulphates of alkaline metals and aluminium or 
some member of the iron group. A univalent and a trivalent 
metal replace the four atoms of hydrogen in 2(H 2 S0 4 ). 

Ammonium ferric alum is NH 4 Fe(S0 4 ) 2 .i2H 2 0. 

Potassium chromium alum is KCr(S0 4 ) 2 .i2H 2 0. 

Alumen Exsiccatum (Dried or Burnt Alum). — The effect of 
heat on alum is first to melt the crystals and next to drive off the 
water, leaving a spongy white mass, which is slowly soluble in 
water, with a local astringent and mild caustic effect on animal 
tissues. 

Toxicology. — Alum coagulates albumin and pepsin and 
retards the peristaltic movements of the bowels, thus arresting 
digestion. When absorbed, it constricts the capillaries, lessening 
mucous secretions, and stopping hemorrhages from capillary 
vessels. It is a prompt irritant emetic, and has so many incom- 
patibles that it is best given alone. 

Excessive doses of this salt have produced irritant symptoms, 
sometimes ending in death. Medicolegal interest in alum is 
practically limited to the question of its action when used as a 
constituent of certain baking-powders which are consumed by 
the ton in domestic bread-making. In these powders sodium 
bicarbonate furnishes gaseous carbon dioxid, which is liberated 
by the action of the alum present, leaving in the bread sodium 
sulphate and aluminium hydroxid. The fact that many thou- 
sands of persons use these powders without any perceptible injury, 
local or systemic, apparently indicates either that the aluminium 
hydroxid escapes solution and absorption or that, if changed to a 
soluble chlorid by the gastic juice, the amount absorbed must 



ALUMINIUM 255 

be harmless. At the same time it is proper to note that large 
doses given to dogs and cats subcutaneously cause paralysis of 
sensation and motion, with fatty degeneration of the liver and 
kidneys. The safest view is to hold alum as an unnecessary 
addition to bread, and certainly of no value as food. Its presence 
in any but the smallest amount should be considered proof of 
adulteration. 

Domestic niters are often fitted with attachments for adding 
alum to the raw and more or less muddy water, with a view to 
causing the formation of gelatinous aluminium hydroxid, which 
entangles the mud and some bacteria in a precipitate that will 
not pass the sand or other porous media. The amount of alum 
required varies from 1 to 10 gr. in the gallon, according to the 
turbidity of the water and the amount of dissolved carbonates 
with which to react. Using judgment, the proportion of alum 
may be kept within the limits of the precipitation, and thus no 
dissolved alum pass into the filtered water. 

Detection. — Having incinerated the organic matter in a plati- 
num dish, the ash should be treated with hydrochloric acid, 
excess of acid removed by heat, a few drops of nitric acid added, 
and a final solution in hydrochloric acid boiled and filtered. 
This acid solution is not changed by potassium ferrocyanid or 
hydrogen sulphid, as are solutions containing the heavy metals. 
Its hydroxid is precipitated from an alkaline solution by hydrogen 
sulphid, or from a neutral solution by ammonium sulphid. With 
potassium hydroxid a white precipitate falls, redissolved by 
excess, whereas an excess of the reagent does not affect the pre- 
cipitate from a solution of the alkaline earths. With ammonium 
hydroxid a white precipitate is formed insoluble in excess. 

Logwood Test. — The most convenient test for alum in bread is 
made with a freshly prepared tincture of logwood. This tincture 
is made by digesting 5 gm. of freshly cut logwood chips with 
100 c.c. of alcohol. Having diluted 5 c.c. of the logwood tincture 
with 90 c.c. of water and added 5 c.c. of saturated solution of 
ammonium carbonate, the mixture is immediately poured over 
10 gm. of bread in a glass dish. After five minutes the liquid is 
poured off, the bread slightly washed, and dried at 100 °C. A 
lavender or dark-blue color denotes that alum is present. Pure 
bread is at first reddish, fading to a yellow or light brown. 

Delicacy. — This test yields a distinct blue with 0.02 per cent. 
of alum, or 7 gr. in a 4-lb. loaf. 

Fallacy. — Several other mineral adulterants produce a some- 
what similar reaction. 

Alum in Drinking Water. — When excess of alum is used in 
filtering water its presence may be detected by the logwood test 



256 THE METALS 

as follows: To the suspected water add fresh tincture of log- 
wood, enough to give a decided color; now add a solution of 
ammonium carbonate. If a blue precipitate fall, then alum is 
present at least 1 : 1000; if no precipitate, but a blue color per- 
sist for an hour, then alum is present at least 1 : 50,000. If before 
the hour be out the color be brown or pink, then there is no 
alum. 

Alum in Baking Powder.— A small quantity of the suspected 
powder is burnt to an ash, which is then treated with boiling 
water and filtered. If the nitrate yields a flocculent precipitate 
when treated with ammonium chlorid, then alum is present in the 
sample. 



WATER SUPPLY 

MINERAL WATERS 



While natural waters usually contain mineral constituents in 
varying proportions, some are so rich in dissolved salts and gases 
as to have a marked taste and a medicinal effect. These spring 
saline waters are grouped according to some important compo- 
nent, as saline, carbonated, chalybeate, alkaline, sulphurous. 

Saline. — Among these may be named Kissingen, Saratoga, 
Seidlitz, Hot Springs of Arkansas. They contain chlorids, sul- 
phates, and carbonates of sodium, potassium, lithium, magnesium, 
and calcium. 

Carbonated. — The best known of these are Apollinaris, Sel- 
lers, and Old Sweet West Virginia. They effervesce with the 
carbon dioxid, which while dissolved enables them to hold in 
solution carbonates of sodium, magnesium, and calcium. 

Sulphurous. — Prominent among these are White Sulphur, 
W. Va.; Sharon, N. Y.; Blue Lick, Ky. They sparkle with the 
dissolved gases, carbon dioxid and hydrogen sulphid, and hold 
in solution chlorids, sulphates, and carbonates of sodium, potas- 
sium, magnesium, calcium, and sometimes iron. 

Alkaline. — Familiar examples are seen in Gettysburg, Pa.; 
Hot Springs, Va.; Buffalo Lithia, Va.; and Vichy, France. They 
contain a large amount of sodium carbonate and lesser amounts 
of chlorids, sulphates, and carbonates of sodium and other metals. 

Chalybeate. — Among well-known iron springs may be men- 
tioned Cresson, Pa.; Rockbridge, Va.; Bath Alum, Va. They 
owe their tonic virtues to the iron sulphate, carbonate, and oxid 
held in solution by the dissolved carbon dioxid. They also con- 
tain sodium, magnesium, and aluminium compounds. 






WATER FOR DOMESTIC USE 257 

WATER FOR DOMESTIC USE 

Water of absolute chemical purity is not found in nature, and 
probably would not be desirable for drinking purposes. Distilled 
water in not palatable; it lacks the ions to which we have grown 
accustomed and which are necessary to health. The natural 
supplies that are preferred instinctively contain a moderate 
amount of mineral matter and some carbon dioxid in solution. 
Water that is hygienically pure is of the first importance to com- 
munities and individuals. It must be palatable, clear, contain 
not more than 15 parts of harmless minerals in 100,000 of water, 
with no lead or other poisons, and be wholly free from the specific 
bacteria of disease. 

Rain water is the primary form of nature, and if it be collected 
in the country and stored in well-made cisterns, is wholesome. 
It may have dissolved from the air traces of ammonia and other 
gases and in the city it may wash down dust particles, some of 
which are organic and bacterial, though in most cases the micro- 
organisms are not disease-producing. Rain water is only rel- 
atively pure. 

Surface Water. — Rain water falling upon the earth becomes 
in part surface water, flowing and remaining above ground. The 
lie of the land causes it to collect in ponds or lakes or to drain 
away in creeks and rivers. In agricultural watersheds the erosion 
by the water increases materially the organic matter, the increase 
being derived from decaying vegetation. The mineral addition, 
however, is very small, and the water remains almost as soft as 
rain water. If the watershed be thickly inhabited, as along the 
banks of some rivers, it may remain wholesome as long as it is 
free from the specific bacteria of disease. Such a water is liable 
at any time to be contaminated by the entrance of bacteria from 
sewage containing excrement from cases of typhoid fever, dysen- 
tery, cholera, or diphtheria. The evidence is incontrovertible that 
drinking water can cause these diseases, and that it does so, 
because of the presence of the peculiar germs. In the cholera 
epidemic of Hamburg, Germany, in 1893, the typhoid-fever out- 
break of Plymouth, Pa., in 1883, and of Ithaca, N. Y., in 1903', 
the dejecta of a single patient passing into the water supply were 
sufficient to cause an enormous amount of mischief. 

Ground=water is that part of the rainfall which sinks through 
the porous earth until it is stopped by a bed of clay or rock. 
The water then moves laterally upon this impervious stratum 
through the permeable soil toward the nearest surface water at 
a lower level. This addition by diluting a river lessens the pro- 
portion of sewage material that the river may have received. 



258 THE METALS 

Sometimes it comes forth again as a natural spring; sometimes 
it is tapped by a well. On its way through the porous soil it 
dissolves out the soluble minerals, but by a natural filtration such 
water is free from organic matter and wholesome, provided it 
has not taken up too much mineral salts to be palatable. Its 
organic purity is due to the fact that it has traversed the home 
of the non-pathogenic bacteria which abide in the surface zone 
of the earth and form a gelatinous layer. Decaying organic matter, 
surface water, and the air furnish the bacteria with their food. By 
the time the water has descended eight or ten feet it has been so 
purified of organic matter that it no longer supports the life of 
micro-organisms. Ordinary house wells are sometimes contam- 
inated and become foci of infection. The mode of access of the 
germs to a well may be by communication from a near cesspit 
through a gravelly stratum, or by the loss of the natural filtra- 
tion powers of the soil through saturation with filth resulting 
from old and crowded communities. 

The pollution of domestic wells is not only by underground 
channels, but also by overflow of foul surface water from barns 
or drains. Deep wells in rural districts give wholesome water 
if properly curbed and covered, and not sunk too near cesspits, 
drains, and stables. 

Hard and Soft Waters. — As a rule, surface waters are said 
to be soft and well waters of a limestone region hard. Hard 
waters are so named because in rinsing the hands, after washing 
them, the water does not clean away from the pores that which 
gave a hard feeling left after lathering. This disagreeable 
residue is made up of the insoluble curds of calcium and mag- 
nesium oleate, resulting from a reaction between the sodium 
oleate of soap and the salts of magnesium and calcium in the 
water. Until these salts are all precipitated as oleate the water 
and the soap are useless detergents, for only then do they form 
a lather. By boiling a hard water carbon dioxid is driven off 
and the soluble calcium and magnesium bicarbonates converted 
into insoluble carbonates, which are precipitated. This process 
softens the water by removal of the temporary hardness. The 
salts remaining in solution, such as the sulphates and chlorids, 
after boiling give to the water its permanent hardness. In laun- 
dries it is customary to soften water and add to its cleansing powers 
by the addition of concentrated lye, sodium, hydroxid; or pearlash, 
potassium carbonate. These precipitate the calcium and mag- 
nesium, salts and give to the water greater penetrating and dis- 
solving power over grease, epithelial debris, and other dirt. 



DRINKING WATER 



259 



DRINKING WATER 

Sand Filters. — Artificial improvement of the house sup- 
ply is commonly obtained by filtering the water through sand 
in domestic filters, aided by the precipitation of suspended matter 
with alum, as described on p. 255. This yields a specimen much 
improved in appearance and in taste, but not with certainty 
deprived of the germs of communicable disease (p. 260). 

Artificial improvement of a town supply is best done after 
the methods of nature. To obtain water like that of springs 
and deep wells for a town or city it is slowly filtered through 
sand. In this way it is purified precisely as is rainfall on passing 
through porous earth. Beds of sand are constructed and thoroughly 
underdrained. The water is permitted to spread over the sur- 
face and percolate through the sand. In a short while a bac- 
terial jelly forms on the surface which performs the same work 
of purification as is done for spring and well waters by the nitri- 




To Pump 



Fig. 61. — Cross-section of filter plant (Jour. A. M. A.). 

fying bacteria that crowd the superficial layers of the earth. The 
high efficiency of slow-working sand filters has been demonstrated 
beyond question. Of many examples, that of the neighboring 
cities, Altona and Hamburg, in Germany, is most celebrated. 

These two cities are both dependent upon the river Elbe for 
their water supply, but the Hamburg intake is above the city, 
while that for Altona is below Hamburg, after it has received the 
sewage of 800,000 persons. In 1893, in Hamburg, the deaths 
from cholera amounted to 1250 per 100,000, and in Altona to 
but 22 per 100,000 of the population. The epidemic spread from 
the Hamburg side up to the boundary line between the two cities 
and there stopped. In one street which separates them the Ham- 
burg side was stricken with cholera, whilst that belonging to Altona 
remained free. In those houses supplied with the Hamburg water 
cholera was rife, while in those furnished with the Altona water 
not one case occurred. The Hamburg water, to start with, was 
comparitively pure when contrasted with the dilute sewage drawn 



260 THE METALS 

from the Elbe by Altona, but, in the latter case, the water was 
submitted to filtration through sand, while in Hamburg the water 
was in its raw condition as drawn from the river. 

Construction of a Town Filter. — The unit filter is a water-tight 
masonry reservoir with an area of one-half to two acres. On the 
floor of the reservoir are perforated underdrains, upon which are 
placed layers of coke or crushed stone and gravel of increasing 
fineness, and last of all a bed of sand 2 to 4 feet deep, which is 
to embody the bacterial jelly. It is highly desirable to have a 
settling basin, through which the raw water must pass before it is 
permitted to flow upon the filter, after leaving its mud behind. 

Storage. — The method of nature in purifying surface waters 
which do not penetrate the porous soil is quiescence, as in the 
case of lakes and ponds. A running stream has very little power 
of self-improvement. A public supply may be drawn from a 
creek or river and stored in reservoirs, leaving it to the ripening 
effects of time. The longer it is stored, the greater the opportunity 
afforded the nitrifying bacteria to destroy the organic matter 
necessary for the sustenance of the germs of disease. The total 
number of bacteria in a surface water is much reduced by storage 
for a while and by slow filtration through sand after. The best 
results in purifying the water and reducing the mortality are 
obtained by using both storage and filtration. 

In case it is impossible to have the water supply treated as 
indicated above, decided improvement can be had by installing 
small filters in houses. These make the water clear, and if prop- 
erly constructed and cared for, lessen the number of bacteria. If 
neglected they become breeding grounds for bacteria and fail to 
be of benefit. The only filters that are germ proof are those 
which force the water through porcelain, such as the Pasteur and 
the Berkfeld. The porcelain tubes should be cleaned every week 
or so, and boiled in water for half an hour. It is well to bake 
them in a stove for half an hour every six months. 

When the drinking water of a household comes under sus- 
picion it should be condemned as raw water, since it can be made 
wholesome by boiling only. Most of the bacteria are killed at 
the boiling-point, but some survive unless the boiling be con- 
tinued for twenty minutes. When thus sterilized the water may 
be recharged with air by a bellows or it may be poured from 
pitcher to pitcher. It may also be drunk as a weak infusion of 
tea or lemonade to make it palatable. 

Examination of Drinking Water.— While chemical anal- 
ysis is not without some importance, especially if no other knowl- 
edge be obtainable, the most significant facts about a water supply 
are often obtained by an engineer's inspection of the watershed 



DRINKING WATER 26 1 

and the surroundings of the reservoir. Every shallow well in 
a densely populated district is unsafe and should be condemned. 
No chemical or bacterial examination is required to determine the 
fact of sewage contamination when drains are seen to enter the 
stream. Any water supply which has once received polluted 
material may, under like conditions, be again contaminated. If 
it be under suspicion, special survey of the territory will often 
point out the particular source of mischief. 

The constitution of ground and surface waters is different even 
when both may be wholesome. The organic matter revealed by 
chemical and bacterial tests applied to a surface water does not 
necessarily condemn it, but would be significant of pollution if 
found in a well water. Correct interpretation of the analysis 
depends upon a knowledge of the source of the sample as well as 
the mode of collection and transportation. 

Biologic Test. — Reliance is fairly well placed upon this test 
properly performed by experts trained in the procedures of the 
bacteriologic laboratory which cannot be adequately presented 
in this work. An approved method is based upon the fact that, 
though there may not be present in the specimen the typhoid 
bacillus or other pathogenic bacteria, there is reason to condemn 
the water when the intestinal organism Bacillus coli communis, by 
its presence, witnesses to sewage contamination. Absence of this 
bacillus, after careful search, would indicate that there is no direct 
access of animal or human feces to the well or other source of 
water supply. 

When sewage is diluted with distilled water, and the mixture 
tested, it has been found that the biologic test will show the presence 
of the Bacillus coli, when the proportion of sewage was so small 
that chemical analysis revealed nothing suspicious. It must be 
recognized that proper bacteriologic methods surpass the chemical 
both in delicacy and in indicating sewage pollution. When such 
evidence is not at hand resort may be had to the following chemical 
tests. 

The value of these quantitative results depends mainly upon 
a comparison with previous analyses made of the same water under 
normal conditions. 

The total solids are determined by weighing a platinum or 
nickel evaporating dish, filling it with i L. of the water, and 
evaporating over a water-bath, drying at no° C. (230 ° F.) or 
over H 2 S0 4 , and weighing dish and residue. On heating to 
redness, charring of the residue would indicate organic matter. 
The total solids should not exceed 500 mg. per liter. 

Chlorids in themselves are not dangerous, but are significant 
because the sodium chlorid of wells and rivers is mainlv derived 



262 THE METALS 

from urine and other domestic waste. A sudden increase in the 
proportion of chlorids points to an access of sewage. In titrating 
for chlorids 100 c.c. of the suspected water is put in a beaker, made 
neutral or alkaline with a drop of sodium hydrate, and colored with 
neutral potassium chromate. Silver nitrate solution is run in from 
a buret until a red color persists. The test solution contains AgN0 3 , 
4.79 gm. per liter, and each cubic centimeter = 0.01 gm. of chlorin 
per liter (0.7 gr. per gallon). In an emergency a water should be 
condemned which shows more than .03 gm. per liter (3 gr. per 
gallon), or which reveals marked increase from its normal amount, 
as determined by previous examinations. 

Organic Matter by Permanganate Process. — The presence 
of organic contamination is revealed by the change of color in 
a pink solution of potassium permanganate. It loses oxygen and 
is reduced to a faintly brownish product. 

Experiment 1. — Put in a beaker 100 c.c. of pure distilled water, 
add 5 c.c. of dilute sulphuric acid, boil on wire gauze and add 5 
drops of dilute permanganate solution (30 mg. in 100 c.c.) and boil 
5 minutes. There is no fading of color. Now add urine or egg 
albumin and boil again; the color is discharged. The number of 
cubic centimeters of a standard pink solution required to overcome 
this fading of color is a measure of organic impurity. 

Ammonia is a characteristic product of the decomposition of 
nitrogenous organic matter, such as urea, and its presence in 
amounts in excess of 0.05 mg. per liter is a danger signal indicative 
of sewage pollution. The free ammonia is obtained by distilling 
the suspected water after adding to it some sodium carbonate, 
leaving a remainder in the flask for the next process. 

Some of the nitrogenous matter of animal origin may be present 
unchanged, and to obtain proof of this it is necessary to break it 
up and separate the nitrogen as albuminoid ammonia. This is 
done by distilling the remainder after subjecting it to the action of 
an alkaline permanganate solution. Pure drinking water does 
not yield more than 0.1 mg. per liter. 

The determination of ammonia lr> the distillate is made by the 
comparison of the yellow color produced by Nessler's solution, 1 
when measured amounts are added to the water, and to a solution 
of ammonium chlorid of known strength. The elaborate part 
of this operation is the distillation. It may be dispensed with if 
free ammonia only is to be determined, the Nesslerizing being 
applied to the original sample after precipitating the calcium salts 

x This is an alkaline mercuric potassium iodid solution made by dissolving 
5 gm. of potassium iodid in hot water and adding a solution of 2.5 gm. of mercuric 
chlorid in 10 c.c. of hot water. The red mixture clears when there is added 
16 gm. of potassium hydroxid in 40 c.c. of water and the whole diluted to make 
100 c.c. 



ARSENIC 263 

with sodium carbonate (one part in ten million of water is detected 
by the yellow color). 

Experiment 2. — Measure 50 c.c. of suspected water in a test- 
tube and add 2 c.c. of Nessler's solution. Look down through the 
tube at a piece of white paper to note if the depth of color equals 
that obtained from a solution of ammonium chlorid of known 
strength. If more than a trace of ammonia is present a precipitate 
falls. The presence of nitrates and nitrites is no longer regarded 
as evidence against the sanitary purity of water, as their source 
may be harmless. Traces are discovered as the result of oxidation 
of harmless constituents. The following test has great delicacy. 

Experiment 3. — Make the reagent first by dissolving 0.5 gm. 
of sulphanilic acid in 150 c.c. of acetic acid (25 per cent.) and 
mixing this with a solution of 0.1 gm. of naphthylamin in 200 c.c. 
of acetic acid. Keep in the dark. Of this reagent put 2 c.c. in 
a well-cleaned beaker with 50 c.c. of water. If nitrites are present 
0.0 1 mg. will give a pink color and larger quantities a rose-red. 

The details of water analysis are too elaborate to be consid- 
ered in this place. They can be found in works devoted to that 
subject alone or to sanitary chemistry in general. 



IV.— THE ARSENIC GROUP 

ARSENIC (Arsenum) 

Symbol As. Atomic weight, 75. 

The element arsenic is considered among the metals because 
its analytic reactions resemble those of antimony and tin, whose 
sulphids are insoluble in dilute acids, but soluble in alkalies and 
in ammonium sulphid. In its chemical affinities it is allied to 
phosphorus so closely that with good reason it might have been 
studied among the non-metals or acid-formers. Its oxids, like 
those of phosphorus, behave as anhydrids of acids. In the fol- 
lowing table resemblances of trivalence and pentavalence are 
shown, which include non-metallic phosphorus with its highly 
developed acid-forming properties; arsenic, a weak acid-former, 
and antimonv, which forms both acids and bases: 



Hydrids. Chlorids. 


Oxids. 


J 


^.cids. 


Sulphids. 


P PH, PCI3 
As AsH 3 AsCl 3 
Sb SbH 3 SbCl 3 


PA - PA 

As, 2 3 — As 2 Os 
Sb 2 3 — Sb.]0 5 


H3PO3 
H 3 As0 3 


- H 3 P0 4 

— H 3 AsQ 4 


P 2 S 3 . 

2 3" 

Sb 2 S 3 . 



All three are irritants and have salts that are poisonous, both 
locally and by their depressing systemic effects. 



264 THE METALS 

Poisoning by some arsenic compound is often resorted to by 
the secret homicide, and comes under notice of the courts more 
frequently than any other form. Taking suicides and homicides 
together, it has caused more deaths than any other poison except 
opium and its derivatives. During the seventeenth century a 
strong solution of white arsenic, known as aqua tophana, was 
widely employed by the poisoners of Italy and France, who were 
convicted only by self-confession. In spite of the fact that modern 
chemistry finds it the easiest of all poisons to detect, it is still used 
not only by suicides, but by criminals, many of whom escape 
punishment for years. Within a period of eighteen months Mrs. 
Robinson of Somerville, Mass., assisted by a quack doctor who 
knew something about arsenic, poisoned in succession five persons 
of her own family without exciting suspicion until her sixth victim 
died. Of 8 deaths of trusting friends laid to her charge, arsenic 
was found in the cadavers of 6. Mrs. Sherman of New Haven, 
Conn., succeeded in escaping suspicion while she killed, succes- 
sively, 3 husbands and 8 other persons of her immediate household 
with arsenic. The peculiar death of her fourth husband led to 
her conviction. 

A case of wholesale poisoning in Havre was revealed by a 
commission of four experts appointed to decide if certain premises 
used as a drug-store were unsanitary. They reported that the 
symptoms of chronic ill-health ascribed to the state of the house 
were in reality due to arsenic poisoning. It was then discovered 
that a clerk, in the course of two years, without exciting suspicion, 
had poisoned 15 persons, 3 of them fatally. They that survived, 
after severe disturbance of the digestive, cutaneous, and respiratory 
organs, were left more or less completely paralyzed. 

White arsenic, or ratsbane, is a favorite poison because it is 
cheap, can be bought as a vermin-killer at any drug-store in the 
United States, and, owing to its very feeble taste, can be mixed 
with the food without the victim recognizing the foreign ingre- 
dient. The acute symptoms simulate indigestion or cholera 
morbus, and thus the physician is misled. It is the practice of 
undertakers to inject sodium arsenate or other arsenic prepara- 
tions into the viscera of a corpse to prevent decay. This places 
an insuperable difficulty in the way of conviction, and knowledge 
of this fact must often embolden the criminal. In the absence 
of rigid restrictions upon the sale of arsenic compounds, such as 
are imposed by other governments, the United States has a bad 
eminence in the number of fatal cases of arsenic poisoning. 

Arsenum or Arsenicum. — Free or elementary arsenic is a 
steel-black mineral with a metallic appearance, when oxygen is 
excluded, subliming at 400 C. (752 ° F.), and when burned in 



ARSENIC 265 

air, at 180 C. (356 F.), emitting an odor of garlic. It is an 
ingredient of some " fly-powders." It is present in commercial 
zinc, iron, and sulphuric acid. It makes a hard alloy with lead, 
is used in the manufacture of shot, and is often found in Brittania 
metal. The insolubility of the element as found in these alloys 
protects us from poisoning by them. Arsenic has been found to 
be the cause of the poisoning induced by eating sardines that had 
been put up in a soldered tin box. The liability of tin and solder 
to contain arsenic leads to the regulation of the French Commis- 
sion of Hygiene that tin should not contain more arsenic than 0.0 1 
in 100. 

In testing, it appears as a black stain on copper in Reinsch's 
test, and as a brown stain on porcelain, and a mirror-like ring on 
glass tubing in Marsh's test. It oxidizes by exposure to the air, 
and in that state becomes poisonous. When volatilized by heat 
it readily unites with oxygen of the air and forms the poisonous 
vapor of white arsenic, As 2 3 (Fig. 67 a). 

Arsenic Terhydrid (AsH 3 ) (Arseniuretted Hydrogen, Arsin, 
Arsonia). — This is a gas generated by the action of nascent hydro- 
gen on reducible arsenic compounds. A hydrogen generator con- 
taining zinc is supplied with dilute sulphuric acid and the arsenic 
solution is added after the hydrogen has filled the apparatus: 

3Z11 + 3H 2 S0 4 + H 3 As0 3 = 3ZnS0 4 + 3H 2 + AsH 3 

Arsenous acid. Zinc sulphate. Arsenic terhydrid. 

The gas is colorless, has an odor of garlic, and burns into water 
and arsenic trioxid: 

2AsH 3 + 30 2 = As 2 O s + 3H 2 0. 

The flame is bluish white or livid, and if a cold body, such as 
porcelain, is put into it, the metallic arsenic is deposited as a brown- 
black spot. The gas, in its course through a small glass tube 
heated to redness, decomposes and leaves its metallic element con- 
densed on the colder part of the tube as a mirror-like ring. Arsin 
has a reducing action upon solutions of silver nitrate, causing 
a black deposit of the metallic silver and liberating arsenous acid. 
It is the most deadly of the inorganic compounds of arsenic. In 
addition to the early symptoms — nausea, shivering, dizziness, and 
prostration — in the severe cases more serious effects appear. 
There may be jaundice, with dark-colored blood, the urine may 
be bloody and suppressed, and coma supervene, ending in death. 

Arsenic trichlorid, AsCl 3 , can be prepared by burning 
arsenic in a current of chlorin. It is a heavy colorless liquid which 
boils at 134 C. (273 ° F.) and is volatile at lower temperatures. 



266 THE METALS 

Hydrochloric acid converts part of arsenic trioxid into chlorid and 
dissolves it. On distilling this solution the arsenic chlorid is found 
in the distillate. By simple evaporation some of this chlorid is 
volatilized and lost. But if arsenic trioxid or arsenous acid be 
converted into arsenic acid by some oxidizing agent, the arsenic 
acid will not be changed to volatile chlorid by the action of hydro- 
chloric acid. Arsenic chlorid is highly poisonous. 

Arsenic Trioxid (As 2 3 ) (Arsenious Oxid, Arsenic, White 
Arsenic, Ratsbane). — Besides the above common names for arsenic 
trioxid, it has another, incorrect, but once official, acidum arsen- 
osum. When dissolved in water it gives a faintly acid reaction 
because it changes to arsenous acid, according to the equation: 
As 2 3 + 3H 2 = 2H 3 As0 3 . This compound, H 3 As0 3 , cannot be 
obtained in the solid state, existing only in solution. Three classes 
of its salts are known according as to whether one, two, or three of 
the hydrogen ions have been replaced by a metal. By losing the 
elements of water it forms meta-arsenous acid, which exists in 
salts known as meta-arsenites, H 3 As0 3 = H 2 + HAs0 2 . By 
roasting its ores arsenic trioxid can be obtained as minute octa- 
hedral crystals, as a smooth, heavy powder, or as irregular 
masses having the appearance of translucent glass and white 
porcelain. The cake of condensed vapor is at first amorphous 
and semitransparent, and is then called vitreous; later, by absorp- 
tion of moisture, it turns to the white, crystalline, opaque, porcelain- 
like variety which has different solubility. The shops usually 
dispense it as a heavy white powder, partly amorphous, partly 
crystalline, prepared from the vitreous variety by grinding. The 
crystalline " flowers of arsenic" obtained by subliming and con- 
densation are made up of octahedral crystals entirely. Samples 
of the powder from different packages vary in microscopic appear- 
ance, and a specimen may often be identified by the size, luster, 
and relative proportion of the crystals it contains. The taste is so 
faint and lacking in distinctness as to be unnoticed when mixed 
with food. While it is sparingly soluble in water, and less so in 
liquid foods, such as milk, beer, coffee, it may easily be suspended 
in thick soups or incorporated with bread as a solid. 

It is extremely unlikely that As 2 3 can be taken into the stomach 
in solution and afterward revert to the solid form. 

Owing to the difference in relative amounts of the two forms 
present in different samples, it is not possible to state the solu- 
bility in precise terms, but usually i fl. oz. of cold water will dis- 
solve from ^ to } gr. (about i : iooo). A permanent solution of 
16 gr. to the fluidounce (about 30 : 1000) can be made by boiling 
water with it for an hour. In spite of the greater weight (specific 
gravity, 3.699), powdered arsenic has the curious property of 



ARSENIC 267 

floating on water as a white film. By adding hydrochloric or 
nitric acid, or by making the water alkaline with the hydroxids 
or carbonates of the alkalis, the arsenic readily dissolves without 
change of color. White arsenic has no odor, but if heated on 
charcoal it is reduced to metallic arsenic, which in vapor has an 
odor of garlic. 

Physiologic Effects. — In the vast majority of cases the local 
action of arsenic is pronounced. It does not corrode dead and 
living tissue alike, as would the corrosive acids and alkalis. Vital 
irritability is required, or the effect on organic matter will be 
small. Applied to a part, it irritates so profoundly that the phe- 
nomena of inflammation appear at once and make rapid progress 
to the latest stage of local death. It blisters the skin like a burn, 
and the mucous surfaces respond with equal promptness to its 
corroding touch. The widespread inflammation of the stomach 
and bowels accounts for numerous cases of rapid death, but the 
greater number of fatal cases do not exhibit sufficient local mis- 
chief to explain the prostration of nervous energy which ends 
in death. To account for the fatty degeneration of important 
organs, such as the heart, liver, and kidneys, the theory has been 
broached that cell protoplasm yields oxygen to arsenous acid, 
converting it into arsenic acid, and later it reverses its action, 
reducing the arsenic acid. These unwonted activities induce 
the morbid changes referred to. 

Medical Uses. — Arsenic is much used in medicine as a general 
tonic for malarial affections and diseases of the skin and nervous 
system. It is given either alone or in combination with remedies 
of the same class. The dose is -gr to -^2 gr. (0.001-0.005 gm.). 

A mode of administration often practised is to give 5 drops of 
the liquor acidi arsenosi (U. S. P.) or of liquor potassii arsenitis 
(U. S. P.) (Fowler's solution), well diluted, after meals, increasing 
the dose 1 drop daily until the disease is under control or until 
the eyelids puff and the bowels move too freely, or faint, darting 
pains are felt in the abdomen. The dose is then reduced to a 
safer quantity, and persisted in until the warning returns, when 
it is again reduced. All this time the arsenic pervades all the 
tissues and can be found in the urine. Occasionally persons are 
encountered who have an idiosyncrasy for arsenic. Even the 
minimum dose will produce unpleasant effects. 

It sometimes happens that the early warnings are ignored and 
the arsenic persisted in until permanent injury is done. The 
usual form of injury is neuritis causing paralysis, local or com- 
plete. 

The incompatibles of arsenous acid are lime-water, tannic acid, 
cinchona, the vegetable astringents, and most metallic salts. 



268 THE METALS 

Symptoms. — If the poison has been in solution and the stomach 
is empty, the symptoms may appear in eight minutes. If taken 
solid and with a meal they may be delayed for as long as ten hours. 
The usual interval before the first signs is from half an hour to an 
hour. If a fatal dose has been taken, the symptoms produced are 
many and various. Departures from the typical forms are fre- 
quent, and no symptoms can be considered as characteristic. 

In acute poisoning, the patient dying within twenty-four hours, 
the symptoms usually come on within an hour. They are those 
of a violent irritant producing local inflammation. Added to 
these, and sometimes occurring independently, are the phenomena 
of collapse and coma, due to the profound involvement of the 
central nervous system. The capillaries of the gastro-intestinal 
tract dilate enormously, become more permeable, and permit the 
escape of the blood-serum which occasions "rice-water" stools. 
The accumulation of the blood in the vessels of the abdomen and 
the loss of blood-plasma tend to bring on collapse and muscular 
cramps. 

The most conspicuous signs are: (i) An excruciating pain in 
the pit of the stomach, aggravated by pressure (this burning pain 
is sometimes absent); (2) sinking sensations and nausea accom- 
pany or may precede the pain; (3) dry mouth, sore throat, and 
urgent thirst are common, but may be absent; (4) persistent and 
forcible vomiting, a sign of an irritability that cannot support the 
blandest drinks: after ejecting the food the stomach throws off 
a rice-water fluid and, later on, a thick mucus, sometimes brown 
from bile and sometimes streaked with blood; (5) purging and 
straining at stools, which may be fetid and bloody, but are apt at 
first to be thin and watery, like those of cholera morbus (this 
purging may be absent or insignificant, and in some cases there 
is obstinate constipation); (6) the urine may be red, bloody, albu- 
minous, scanty, and even suppressed; (7) a feeble, frequent, and 
irregular pulse ushers in the other symptoms of collapse, the 
livid and anxious face, sunken eyes, cold and clammy skin; (8) 
cramps in the calves of the legs, restlessness, spasms ending in 
unconsciousness. 

A small proportion of the cases are classed as nervous or cere- 
bral, because the central nervous system is prominently affected, 
while the local irritant symptoms, such as vomiting and purging, 
are slight or wholly absent. The conspicuous nervous phenomena 
are great prostration, stupor, convulsions, paralysis, collapse, and 
death in coma. 

A subacute form is one favored by ingenious criminals who 
give the poison in small doses, repeated at intervals, so as to cause 
death by gradual prostration through stages relatively slow. The 



ARSENIC 269 

symptoms make their onset later and are less violent than those 
of the typical acute form. Most of the cases are of this variety; 
sooner or later there will be loss of appetite, fainting sensations, 
nausea, dry throat, retching, shooting pains referred to the stom- 
ach and intestines, and diarrhea. These merge into vomiting, 
great abdominal tenderness, tenesmus with bloody stools, scanty 
and albuminous urine, jaundice, eczema or erythema, nervous 
weakness, feelings of numbness and tingling in the extremities, 
muscular pains, cramps, paralysis, convulsions, and coma. 

Under proper treatment the acute symptoms may subside, and 
some days or even weeks afterward sequelae will appear. These 
are attributable to a chronic inflammation of the peripheral nerves, 
ending in degeneration of the fibers extending from the periphery 
toward the center, causing loss of sensibility and paralysis in the 
hands or feet, which may progress until the muscles waste and 
give the electric response known as the reaction of degeneration. 

Anomalous Cases. — Emphasis should be placed upon the 
statement above, that no symptoms can be considered character- 
istic. Fatal cases have been reported which presented typic 
postmortem appearances, and yet during life exhibited no pain, 
vomiting, or purging, and in which thirst was not marked in degree. 

Fatal Dose. — Two grains is the smallest fatal dose of white 
arsenic yet reported. Suicide was accomplished in the case of a 
woman who had recently aborted, by taking \ fl. oz. of Fowler's 
solution, equal to 2 gr. of arsenic trioxid, in broken doses, within 
four days. Three grains of absorbed arsenic would probably 
prove fatal to an average man. 

Recovery is possible after much larger quantities, as the symp- 
toms vary according to the bodily condition of the person, the 
state of the stomach, and the form of the poison. Remarkable 
recovery may ensue if the poison is taken in lumps or if vomiting 
evacuates the stomach before absorption has set in. .. 

Fatal Period. — The shortest interval before death is twenty 
minutes. A large dose may overwhelm the entire nervous sys- 
tem, so as to bring about collapse and coma within the hour. The 
average period is about twenty-four hours. In the subacute cases 
the fatal termination may not occur for several weeks. 

Treatment. — The first indication is to evacuate the stomach by 
administering an emetic mixture of a teaspoonful of mustard and 
a tablespoonful of salt in a tumbler of warm water. This may be 
repeated in ten minutes, or hypodermic injection (5 drops of a 2 
per cent, solution) of apomorphin, or an emetic dose of sulphate of 
zinc can be given. Where criminal poisoning is suspected, tartar 
emetic should be avoided, as it will make detection of arsenic more 
difficult. The stomach-tube will prove valuable if the stomach 



270 THE METALS 

is not full of mixed food, pieces of which would occlude the open- 
ings in the tube. Large drafts of hot milk and water will facilitate 
the washing out of the poison. At the same time the antidote may 
be given to make the residue insoluble and inert. For this purpose 
reliance is placed on teaspoonful doses of dialyzed iron or on the 
freshly made moist ferric hydroxid, to convert the arsenous acid 
into ferric arsenite, which is only very sparingly soluble (p. 34 1 )- 

Fe(HO) 3 + H 3 As0 3 = FeAsO s + sB. 2 0. 

Ferric hydroxid. Arsenous acid. Ferric arsenite. 

In the official preparation, Jerri hydroxidum cum magnesii 
oxido (U. S. P.), two antidotes are combined. This may be pre- 
pared extemporaneously by diluting J oz. of tinctura Jerri chloridi 
with a tumbler of water and adding magnesia in excess. The 
whole mixture may be taken without straining and repeated sev- 
eral times. The arsenous acid forms insoluble ferric and mag- 
nesium arsenites. If the ferric hydroxid is prepared by adding 
ammonia water to ferric sulphate or ferric chlorid, then the gelat- 
inous precipitate should be separated from the excess of ammonia 
by straining through a handkerchief or piece of cheesecloth. To 
clear the intestine a dose of castor oil should be given. In spite 
of evacuants and antidote it sometimes happens that the poison 
in the form of a powder adheres unchanged to the folds of the 
mucous membrane. 

Postmortem Appearances. — Putrefactive change is usually 
retarded when the body is permeated with arsenic. If the dose 
has been large and life prolonged until absorption could take place, 
this preservative effect will often keep the viscera free from gases 
and putrid odors for as long as seventeen months. A smaller 
dose, especially if rapidly followed by death before general diffusion 
could occur, would not have the same action. The pathologic 
changes induced are usually those of gastro-enteritis common 
to the class of local irritants of the stomach and bowels, and 
if the patient should survive for a number of hours, the absorbed 
poison will set up fatty degeneration of the heart, liver, and kidneys. 

Mouth, Pharynx, and Esophagus. — The repeated acts of vom- 
iting bring the poison up from the stomach more or less dissolved 
and active. Inflammatory change sets in at once, and the upper 
part of the alimentary tract will present enlarged vessels, reddened 
patches, and erosions. 

Stomach. — The lining membrane of the stomach may be cov- 
ered with a tough mucus or lymph in which white particles of 
the poison will be imbedded, or, if Paris green has been taken, 
there may be patches of a bright green color. Sometimes the 
arsenic penetrating the gastric walls as far as the peritoneum has 



ARSENIC 271 

been turned into yellow sulphid by the reaction with hydrogen 
sulphid of putrefaction. The mucus itself may be abundant and 
dark, containing blood. Small dark red dots of effused blood, 
looking like flea-bites, may stud the surface of the membrane, 
itself a paler red, obviously due to diffused inflammation. Upon 
the prominent folds of the mucous membrane these effusions may 
run together in well-marked streaks of dark-red color. The 
inflammation may involve the other coats of the stomach, and 
all of them be found thickened and corrugated. Occasionally, 
localized gangrene ensues. Rarely does the inflammation pro- 
gress to ulceration, and still more rarely does the ulcer involve the 
whole structure, causing perforation. 

While some degree of gastric inflammation will nearly always 
be found, it is important to note that death may occur from the 
cerebral effects ending in coma, while the mischief done to the 
stomach may be insignificant. 

Intestines. — If death be delayed for several days, the whole 
length of the intestinal tract may be inflamed, but usually the 
small intestine, and more frequently the duodenum, alone will be 
involved. There is diffused redness, with scattered patches of a 
deeper hue, and the contents may be bloody, or perhaps yellow 
from the formation of yellow sulphid. Like the stomach, the 
intestines may show little or no sign of inflammation, even with 
the arsenic present in considerable amount, the death being due 
to the effect on the central nervous system. 

Changes in remote parts may occur if life be prolonged for a 
number of hours, and are most conspicuous in the heart, liver, 
and kidneys. Any or all of these may show fatty degeneration. 
The heart is the seat of effusions of blood under the endocardium, 
especially of the left ventricle. 

Chronic Poisoning. — Peculiar features are found in chronic 
poisoning that have given rise to the theory that arsenic is cumu- 
lative. Careful investigation shows that the poison is not stored 
up in the tissues for such a length of time as are lead and mercury, 
though the effects appear to accumulate in force and gravity. 

Arsenic is readily diffusible and, passing to the tissues, abides 
for a few weeks and then is eliminated. The dose may be con- 
siderable, yet if the patient lives for three weeks the arsenic may 
have entirely disappeared from the soft tissues, but may still be 
detected in the bones. On the other hand, cases are recorded 
where the poison has been found in the liver and bones after two 
and even six months. 

The poison has been known to enter by many avenues — inhaled 
by the lungs, swallowed in food or as excessive medication, applied 
to the skin by mistake in cosmetics or in the red dye of socks and 



272 THE METALS 

gloves. The person falls into "poor health," losing appetite 
and all desire for exertion. Soon twinges of pain, especially 
sudden colic, will appear. Complaint is made of "sickness" and 
faintness. The eyelids puff, the conjunctiva is reddened, and 
the eyes become very sensitive to light. Such signs of indigestion 
as occasional vomiting, colic, and chronic diarrhea arise. The 
color fades from the face, the complexion becoming waxy. The 
person is said to have a wasting fever. Progressive weakness 
and loss of weight prevail throughout. The hair becomes dry 
and may fall out, and the nails are brittle and loose. The skin 
may exfoliate or show spots of darker hue, with eruptions of 
eczema or erythema. The mouth may lose patches of mucous 
membrane, form ulcers, and show the symptoms of salivation. 
The throat, nose, larynx, and bronchial tubes may be affected with 
a catarrh, causing cough, bloody expectoration, aphonia, and 
copious coryza. At a later period the nerve-fibers become inflamed 
and degeneration of this structure is a consequence. At first the 
sensory nerves indicate the mischief going on by attacks of numb- 
ness and tingling in the extremities, which are followed eventually 
by total absence of normal sensation, or, it may be, by pain and 
tenderness. When the motor nerves of the hands and feet are 
involved there are loss of power in them and wasting of the affected 
muscles. Even if the poison is discontinued, the paralysis usually 
lasts for many months, recovery being very slow and generally 
incomplete. The paralysis may extend until it is general, and 
death ensue from failure of the heart due to fatty degeneration. 
A horny condition of the palms and soles, or keratosis, may be 
produced by the long-continued use of arsenic as a remedy in 
chronic psoriasis. 

Arsenic Applications. — Deaths have been recorded from 
applications of arsenic, with homicidal intent, to the rectum and 
the vagina. It has poisoned when used as an urethral injection. 

In these cases of absorption from other mucous surfaces and 
also when applied to the unbroken skin, as ointment, lotion, or 
powder, the symptoms are much the same as when taken into the 
stomach. There is, first, a local inflammation, soon followed 
by nausea, vomiting, thirst, abdominal pain, diarrhea, suppressed 
urine, and nervous symptoms. 

An arsenic ointment applied to the scalp of a child to cure an 
eruption caused death in ten days, with symptoms of gastro- 
enteritis. By mistake white arsenic was dispensed for a dusting- 
powder to the skin, with fatal consequences to 17 children. 
Arsenic plasters used to remove tumors have had severe systemic 
effects, and even death has been caused by them. In such cases 
the poison has been found to be distributed throughout the body. 



ARSENIC 273 

Arsenic-eating. — It has been proved indubitably that in Styria, 
Lower Austria, and India individuals have been found who, by 
carefully increasing the dose at long intervals, have accustomed 
themselves to take with impunity what in others would produce 
poisonous symptoms. 

These arsenic-eaters take for twenty or thirty years from J to 2 
gr. or even more of arsenic trioxid at intervals of once a week or 
oftener, with the intent to increase their powers of endurance. 
The persons examined have been robust men who lead an active 
mountain-climbing life. It is not unlikely that to a high Consti- 
tutional power of resistance they add an unusual activity of the 
excretory organs. They appear to be especially liable to sudden 
death. 

Popular writers have helped to create the impression that there 
are village communities who indulge themselves in arsenic as 
others do in tobacco. This is not well founded, nor is there evi- 
dence to support the opinion that moderate arsenic-taking is com- 
mon among persons who wish to improve their complexion. 
Among its transient pathologic effects are a clear pallor, sometimes 
a circumscribed flushing of the cheeks, and a glistening of the eye. 
These soon pass into a waxy skin and puffy eyelids — anything 
but pleasing to look upon. Very rarely it happens that a person 
for whom Fowler's solution has been prescribed will take it of his 
own volition to restore his health, but a persistence in the habit is 
soon found to be prejudicial and the dose given up. Physicians 
consider it doubtful if any considerable number of persons find it 
compatible with comfort for more than a brief period. 

Tests for Arsenic in the Solid Form. 1 — When undissolved, 
it is easy to recognize the poison by heating it in a sublimation 
tube and applying other tests to the deposited vapor. 

Sublimation Test. — Arsenic trioxid sublimes without fusing at 
a temperature lower than 218 C. (424 F.), the sublimate under 
a lens presenting octahedra and modified forms, such as tetrahedra 
and dodecahedra (Fig. 62, c). 

1 The duty of the physician in attendance, who suspects poison during life, is 
to examine the vomited matters, urine, or feces by some test such as Reinsch s. 
Having discovered arsenic, if the case ends fatally, he should inform the state 
prosecutor and insist on a post-mortem which, if possible, should be held in the 
presence of the chemical expert. Having tied the esophagus just above and the 
intestines just below the stomach, another ligature is applied at the lower end of 
the gut and the whole tract between with contents is removed without opening. 
The stomach and intestines are then put in a clean new jar with glass stopper, 
sealed with paraffin and fastened by sealed cords. In the same way the brain 
is sealed up in a separate jar and in another jar the liver, spleen, kidneys, and a 
piece of muscular tissue. Any urine in the bladder or vomited matters must be 
put in clean new bottles. 

The sealed containers must be kept locked up until delivered to the chemist 
by the physician. 

18 



274 



THE METALS 



Fallacies. — The octahedral form distinguishes the minute 
arsenic crystals from other volatile white solids subliming at this 
temperature, such as corrosive sublimate, calomel, and oxalic 
acid. While many authorities assert that the sublimate of anti- 
mony oxid is always amorphous, according to others it may 
sometimes occur as octahedral crystals like arsenic. 

Reduction Test. — This test is applied to any solid compound of 
arsenic, including Paris green, the two sulphids, and any arsenite. 
The dry substance is introduced into a reduction tube, part of 
which has been drawn out to a small caliber at the bottom. It is 
covered with six times the quantity of a well-dried mixture of 3 
parts of sodium carbonate to 1 part of potassium cyanid. Heated 




Fig. 62. 



and b are two reduction tubes showing arsenic mirror after reduction test; c, octahedra of 
AS2O3 sublimate, magnified. 



gently, some moisture may first appear on the tube. This can be 
removed with a spiral of filter-paper, a swab of absorbent cotton, 
or by gently heating the moist glass. When the tube is dry, strong 
heat is applied to the flux and then to the arsenic. The arsenic 
compound is reduced to metallic arsenic, which is deposited higher 
up on the tube as a mirror-like ring, black shading to brown or 
gray (Fig. 62, a and b). 

Fallacies. — The compounds of antimony yield no mirror with 
this flux, but the compounds of mercury, cadmium, tellurium, 
and selenium may. When viewed by a lens the mercury mirror 
is found to have a fringe of globules. To distinguish the arsenic 
mirror the end of the tube must be broken off and the ring heated 



ARSENIC 275 

with the tube aslant. The air playing over the hot arsenic will 
oxidize it, and the mirror will be vaporized and appear on the 
cooler parts of the tube as minute white crystals of arsenic trioxid, 
octahedral in form (Fig. 62, c). If another specimen is treated 
with a warm solution of chlorinated lime, the mirror will dissolve 
in a manner characteristic of arsenic. 

Delicacy. — If roVo g r - of arsenic be tested in a tube contracted 
to ■£$ in. in diameter, it yields a visible sublimate which will re- 
sublime and show many crystals of arsenic trioxid. 

Tests for Arsenic in Simple Solutions.— When the poison has 
been obtained in solution free from organic or other matter, the 
following tests will help to identify it: 

Ammoniosulphate of Copper Test. — Enough of the reagents 
for the test can be freshly made by putting about 5 drops of ammo- 
nium hydroxid in a test-tube and diluting it with 10 c.c. (3 fl. dr.) 
of water. To this dilute ammonia-water a weak solution of copper 
sulphate is added until the bluish-white precipitate ceases to dis- 
solve. The slight excess of cupric hydroxid should be removed by 
filtration. The clear-blue solution added to a solution of arsenic 
trioxid will throw down a bright-green precipitate of cupric arsenite, 
CuHAs0 3 {ScheeWs green) (Plate 2, No. 2). A portion treated 
with ammonium hydroxid dissolves as a clear-blue liquid; another 
portion will make a colorless solution with nitric acid. 

Fallacies. — While no metal but arsenic yields the green pre- 
cipitate, different organic substances give a green color, and, 
therefore, interfere with it. The arsenic precipitate, when dried 
and subjected to the reduction test, will give the metallic mirror. 
Dissolved in hydrochloric acid and subjected to Reinsch's test, 
the metal deposit will show on copper-foil. 

Delicacy. — A green response has been obtained from tooto g r - 
of arsenic. 

Ammonionitrate of Silver Test. — To prepare the reagent 
freshly dilute some ammonium hydroxid, as stated in the last test, 
and add to it a strong solution of silver nitrate until the precipitate 
of silver oxid formed ceases to dissolve. This reagent yields 
with solutions of arsenic trioxid a canary-yellow precipitate of 
silver arsenite, Ag 3 As0 3 (No. 3, Plate 2), which dissolves in 
ammonium hydroxid and in nitric acid, but not in sodium 
hydroxid. If dried and heated with flux, as in the reduction test, 
silver arsenite will be identified by the metallic mirror formed on 
the cooler part of the tube. 

Fallacies. — Other chemicals, such as phosphoric acid, the alka- 
line iodids, and bromids, will give a like yellow precipitate. 

Interferences. — The chlorids, hydrochloric acid, and organic 
matter decompose the reagent and interfere with this test. 



276 



THE METALS 



Delicacy. — Minute yellow flakes are yielded by to wo g r - 

Bettendorff's Test. — A freshly made solution of stannous 
chlorid is added to the suspected material dissolved in strong 
hydrochloric acid. Having immersed a small piece of pure tinfoil, 
the mixture is heated; if arsenic be present, a brown color or a gray- 
brown precipitate of the metal is formed. 

Delicacy. — A brown coloration is yielded by too 00 g r - forming 
5W0T0" of the hydrochloric-acid mixture. 

Tests for Arsenic in Complex Solutions.— To detect the arsenic 
in solutions with other matters the following tests are useful: 

Hydrogen Sulphid and Hydrochloric Acid Test. — If the 
solution, acidified with hydrochloric acid and warmed, be sub- 
jected to a current of well-washed hydrogen sulphid, bright-yellow 
arsenic sulphid, As 2 S 3 (No. 1, Plate 2), will be thrown down. 



2 Ho As O, 



+ 



3H 2 S 



6H 9 



+ 



/1.S2O3. 




This deposit is insoluble in cold hydrochlric acid, but hot nitric 
acid decomposes it and forms solution of arsenic acid. It will 
dissolve in the alkalis and in ammonium 
sulphid. 

Fallacies. — Yellow or orange precipi- 
tates may occur from cadmium, anti- 
mony, and tin, and the possible separa- 
tion of sulphur from the hydrogen sul- 
phid. To verify the nature of the precipi- 
tate it should be separated by filtration, 
dissolved in ammonia, evaporated to dry- 
ness, and subjected to the reduction test 
and the resubliming of the metallic mirror 
to octahedral crystals. 

Delicacy. — A yellow turbidity, ending 
in a good deposit, has been obtained from 
Towo gr. 

Gutzeit's Test. — In a test-tube contain- 
ing 1 c.c. of the suspected solution, either 
acid or neutral, put about 1 gm. of chemi- 
cally pure zinc and 5 c.c. of a 6 per cent, 
dilution of sulphuric acid. In the upper 
part of the tube insert a plug of absorbent 
cotton moistened with lead acetate, and 
clasp over the mouth of the tube a cap 
made of three layers of filter-paper. Hav- 
ing wet only the upper layer with a drop 
of saturated solution of silver nitrate, set aside in a dark box for 
a time. Arsenic will cause on the paper a bright yellow spot, 



Fig. 63. — Apparatus for Gut 
zeit's test for arsenic. 



PLATE 2. 



Arsenous sulphid produced in hydrogen sulphid and hydrochloric acid test 

for arsenic. 



Cupric arsenite produced in ammonio-sulphate of copper test for arsenic. 



Silver arsenite produced in ammonio-nitrate of silver test for arsenic. 



Silver arsenate produced in arsenic solutions by treatment with silver 

nitrate. 



Antimonous sulphid produced in hydrogen sulphid test for antimony. 



Stannic sulphid produced in hydrogen sulphid test for stannic compounds. 



ARSENIC 



277 



which darkens by separation of metallic silver when water is 
applied to it (Fig. 63). 

AsHs + 6AgN03 + 3H 2 = 6HN03 + H s As03 + 6Ag. 

The color made by antimony is at no time yellow, but is at 
once brown or black. 

Reinsch's Test. — The purity of the materials for this test may 
be established by a blank experiment. A few slips of bright 
copper-foil should be put into pure water containing one-sixth 
part of hydrochloric acid, and then heat applied so as to boil for 
five minutes. The copper remaining bright, the hydrochloric acid 
may be assumed to be pure; but every detail of this test and others 
must be paralleled by blank experiments before the analyst can be 
sure. 1 Having added one-sixth volume of hydrochloric acid to the 
solution to be tested, a strip of pure copper-foil is put into it and 
the whole boiled for a few minutes. If arsenic be present, as 
arsenous acid or arsenites, it is deposited as a dark film, purple to 
steel gray in color. From arsenic acid it is deposited only when 
the solutions are strong. 

Fallacies. — A coating will be left on the copper by arsenic, 
antimony, mercury, bismuth, gold, and platinum; even prolonged 
boiling in hydrochloric acid may tarnish it. To verify the arsenic 
film the copper slip should be washed, dried with filter-paper, 
rolled into a cylinder, and inserted into a hard glass tube open at 
both ends, all by means of forceps, the finger not touching the foil. 
When the heat of a spirit lamp is applied, the metallic film sublimes 
and is deposited on the tube as a white ring of octahedral crystals 
of arsenic trioxid, which will dissolve in water and respond to 
ammonionitrate of silver and the other tests given above. 

Beside arsenic there are two other metals, antimony and mer- 
cury, which make a sublimate under .these conditions. Mercury 
makes a sublimate of shining globules; the antimony sublimate 
is generally amorphous, but may be in octahedral crystals. 

To establish the arsenic nature of the sublimate the octahedral 
crystals must be well defined. In order to get the crystals depos- 
ited on a glass slide convenient for the use of J-in. objective, the 
following manipulations will be useful: Having obtained the 
arsenic stain on copper-foil, the foil is removed, washed, and dried 
without contact with the fingers, and cut into narrow strips. A 
subliming tube should be made of thin glass, diameter \ in., length 
if in., sealed at one end, and a lip turned back at the other open 

1 As ordinary copper itself may contain arsenic, it should be tested by first giving 
it a polished surface and then dropping a sample into a boiling mixture of equal 
parts of solution of chlorid of iron and pure strong hydrochloric acid. If impure, 
arsenic will show as a black coating. 



278 



THE METALS 



end, so that it will hold when hung in an opening made in a sheet 
of brass 4 in. X 2 in. The sheet of brass should be laid upon 
the ring of a retort stand, with the tube suspended, and then 
the tube warmed, so as to dry it. After cooling, the tube receives 
the strips, and a microscope slide, dried by heat, is placed upon it. 
The glass subliming-tube should then be heated, so as to permit 
the flame to play also on the bottom of the brass plate. A whitish 
sublimate will appear on the glass slide in a few seconds, but the 
heat should not be withdrawn until the white patch begins to 
clear up at the edges and has a diameter of J in. The cold slide 




Fig. 64. — Sublimate of arsenic trioxid (magnified 340 diameters). 



examined by a \- or J-in. objective will show minute octahedra 
and tetrahedra, and modifications of these (see Fig. 64). 

Interferences. — This test does not work properly if nitric acid, 
a chlorate, manganese dioxid, or other oxidizing agent is present. 
They cause the solution of the copper and prevent the formation 
of an arsenic coating. With this simple and delicate test it is 
possible for the physician to make an early diagnosis during life 
by examining the vomited matters or urine without any other 
preparation of the materials than digestion on the water-bath with 
1 part of pure hydrochloric acid to 6 of the tested fluid. The 
copper slips can then be boiled in this fluid. Any marked dark- 
ening of the copper is significant usually of arsenic, antimony, or 
mercury. 



ARSENIC 



279 



Delicacy. — With ordinary reduction tubes distinct octahedra 
form when only tottoo" g r - of arsenic is present; with great care, 
using very fine t'jbes, tooto g r - na s been revealed. 

Marsh's Test. — When hydrogen is generated in the presence of 
compounds of arsenic, they give up the arsenic, which, uniting 
with hydrogen, forms arsenic terhydrid, AsH 3 (p. 265). This 
is a gas which, by heat, yields the metallic arsenic for identification 
by tests already stated. In a flask arranged for generating hydro- 
gen (Fig. 65), with air-tight connections, pure zinc is placed 1 
and pure cold dilute sulphuric acid (1 : 6) is added to it through 
the funnel-tube (b). The gas is first conducted through a drying 
tube containing calcium chlorid (a) between plugs of glass wool, 




Fig. 65. — Marsh's apparatus for the detection of arsenic. 

and then through an exit tube of hard glass, about 5 mm. (y^ in.) 
internal diameter, and 25 to 50 cm. (10-20 in.) long, which is 
turned up at the end and drawn out at the tip to make a jet. After 
waiting a few minutes for the air in the apparatus to escape a 
Bunsen flame is applied in the course of the exit tube, which is 
heated to a low red heat, and if no stain appears on the glass 
after fifteen minutes, the chemicals may be considered pure. The 
gas jet should be ignited, and if arsenic fluid is now poured in by 
the funnel tube in small portions, the pale hydrogen jet becomes 
more luminous and livid in color. If organic matter should cause 
much frothing, a small quantity of alcohol may be introduced by 
the funnel tube. 

1 When pure zinc is used the evolution of hydrogen should be accelerated by a 
few drops of solution of platinum chlorid. 



280 



THE METALS 



Marsh 1 s Original Method. — To prove the presence of arsenic 
in the gas Marsh proposed to condense the free metal on cold 
porcelain held in the flame (Fig. 65, c). It is like a spot of soot: 
black or seal brown. Many spots can be obtained upon evapo- 
rating dishes or crucible lids and tested later by different reagents 
to distinguish them from the antimony stains which they resemble 
closely. 

Berzelius' Modification. — The most delicate, reliable, and, 
indeed, necessary method for detecting the arsenic with the Marsh 
apparatus for forensic purposes is to heat the gas while passing 
through the long exit-tube by applying to it one or more burners 




Fig. 66. — Modification of Marsh's apparatus to secure the most delicate results: a, Generating 
bottle; b, calcium chlorid tube; c, point where hard glass tube narrows from I to J in., a small plug of 
asbestos inside; d, a small plug of asbestos; between c and d a mixture of dry sodium carbonate and 
charcoal; e, a fire-clay chimney if in. in diameter, with a thin bridge of fire-clay to support the tube 
between c and d; h, a strip of muslin \ in. wide wrapped around the tube and tied. 



with chimneys to confine the heat. For the best results the tube 
may be constricted at points just beyond the part heated, and the 
constricted part kept cold by a wet muslin strip (Fig. 66, h). 

If a dull red heat is maintained for an hour, all the arsenic will 
be separated from the mixture and collected as a mirror-like ring 
inside the tube between k and the strip of wet muslin. The dis- 
crimination tests given below can be used to confirm the arsenic 
nature of this metallic ring, as well as for the spots on porcelain. 

Fallacies. — Antimony is deposited under the same conditions 
as arsenic, and in a form closely resembling it, whether in the spots 
on porcelain or the mirror-like ring in the heated tube, but the 



ARSENIC 



28l 



arsenic mirror is at a little distance beyond the flame and brownish, 
shading to black (Fig. 67, a), while the antimony is close to the 
flame, sometimes on both sides of it, and tin-like in luster. 

The arsenic stains are soluble in warm solution of calx chlorinata 
or liquor soda chlorinata, while the antimony is insoluble, or only 
very slowly and sparingly soluble. Dissolved by heating gently 
with a few drops of a solution of ammonium molybdate in nitric 
acid, the arsenic gives a yellow precipitate, whereas antimony 
forms none. Another deposit dissolved in nitric acid and dried 
by cautiously heating leaves a whitish spot which, if arsenic, 
a b 

As. Sb. 




Fig. 67. — a, Mirror of arsenic: b, mirror of antimony; c, reaction of As with HXO3 and AgX0 3 ; d, 
reaction of Sb with HXO3 and AgX0 3 . 

turns red when touched by a drop of strong solution of silver 
nitrate (Fig. 67, c)\ if antimony, there is no change of color (Fig. 
67, d). Another deposit, if arsenic, dissolves in ammonium sulphid 
and on evaporation leaves a yellow stain soluble in ammonia, but 
insoluble in hydrochloric acid. The residue of antimony sulphid 
would be orange-red, insoluble in ammonia, but soluble in strong 
hydrochloric acid. 

The extraordinary sensitiveness of most of the tests for arsenic 
requires that the analyst should be very careful that the apparatus 
is clean and the chemicals are of ascertained purity. In medico- 
legal analysis it is well to carry on simultaneously a parallel blank 



282 THE METALS 

examination, similar in every respect but that of containing the 
suspected matters. Traces of arsenic have been found in zinc, 
copper, sulphuric acid, hydrochloric acid, even in filter-paper, 
and in common illuminating gas. Glass vessels that have been 
cleaned with shot may have enough left on them to lead to a false 
conclusion. 

Interferences. — The perfection of Marsh's test is impaired if 
chlorids, hydrochloric acid, nitrous compounds, or nitric acid be 
present. If salts of silver or mercury be present, they may decom- 
pose the arsenic terhydrid in the flask as soon as it is generated. 

Delicacy. — To operate this test even on a small scale requires 
at least 100 gr. of the liquid. The least amount that would yield 
a satisfactory spot on porcelain is about -5-0V0 gr. of arsenic trioxid. 
When the gas is not ignited, but heated in the exit tube so as to 
get all the free metal at one point, we get a degree of sensitiveness 
beyond that reached by any other test known to chemistry. By 
this Berzelius' modification of Marsh's test a characteristic deposit 
on the glass can be obtained from -sowo g r - dissolved in 100 gr. 
of liquid. 

Fleitmann's Test. — When zinc or aluminum is heated with ex- 
cess of potassium hydroxid or sodium hydroxid in a mixture contain- 
ing arsenic trioxid or trisulphid, the gas arsenic terhydrid is evolved: 

Zn + 2KHO = K 2 Zn0 2 + H 2 . 

The apparatus required is a generating flask with a delivery 
tube dipping into a 4-per cent, solution of silver nitrate. It is 
sometimes more convenient to use a test-tube covered with filter- 
paper wet with silver nitrate, as in Gutzeit's test (Fig. 63). The 
suspected liquid, made strongly alkaline with pure sodium or 
potassium hydroxid, is put in the flask or the test-tube with a 
few pieces of sheet aluminum or pure zinc and gently heated. 
The arsenic terhydrid reduces the silver as a black precipitate, 
leaving arsenic trioxid and nitric acid in solution. If the test- 
tube is used, a black spot appears on the paper cover. By means 
of this test we can detect arsenic in the presence of antimony, as 
antimony terhydrid is not evolved by it. It will not detect arsenic 
as arsenic acid, and as it forms solid hydrid in the flask, holding 
back one-fifth of the arsenic present, it is not available for quanti- 
tative purposes. It is liable to a fallacy from the fact that free 
hydrogen after some time and phosphin both reduce the silver 
nitrate; hence, the presence of arsenic trioxid in the silver solution 
must be proved by other tests. 

Detection in Gastric Contents and Viscera. — The vomited 
matter should be spread in a thin layer on a large dish and care- 
fully searched for grains of white arsenic, Paris green, or yellow 



ARSENIC 283 

sulphid. For casual or preliminary examination the suspected 
material may be treated as suggested above by Reinsch's test. 
The presence of the smallest amount is significant, as arsenic is 
not a constituent of the body in general, nor should it be present in 
the food. If any compound of arsenic should be found free in the 
gastric contents, or if it should be obtained by testing, a specimen 
of it must be carefully marked and set aside to show in court. 

When it is desired to make a quantitative estimate, it is neces- 
sary to destroy the organic matter. This may be done by mincing 
the tissue into fine shreds, bruising these in a mortar, heating 
over a water-bath in pure dilute hydrochloric acid (best made in 
the laboratory), and adding, from time to time, small portions of 
potassium chlorate until the solids are completely dissolved in a 
clear yellow fluid and continuing a gentle heat until the odor of 
chlorin disappears. This fluid is treated with solution of sulphur 
dioxid to reduce the arsenic compound to the arsenous form, then 
concentrated on a water-bath and filtered. A slow stream of 
hydrogen sulphid passed through the filtrate will precipitate the 
arsenic as arsenous sulphid with other matter. The precipitate is 
collected on a filter, thoroughly washed, and treated with ammonia- 
water, which dissolves out the arsenous sulphid, leaving various 
impurities behind. The filtered solution is evaporated to dryness 
in a porcelain dish, the residue warmed with strong nitric acid 
until completely oxidized, and solution of sodium hydroxid added 
in slight excess. The mixture is evaporated to dryness, the resi- 
due moistened with pure sulphuric acid, and heated cautiously on 
a sand-bath until fumes cease to escape. The carbonaceous 
product is boiled out with acidulated water and the solution filtered. 
The filtrate should be colorless, and, if the process has been properly 
executed, contains all the arsenic free from organic matter. As 
the arsenic generally exists in the solution wholly or in part as 
arsenic acid, sulphurous acid should be added to reduce it to the 
arsenous condition, and the mixture gently heated until all excess 
of the sulphur dioxid has been expelled. A definite part of this 
solution may be reserved for determining the amount of arsenic 
by precipitation with hydrogen sulphid, as described below, while 
the remainder may be subjected to Reinsch's, Marsh's, and other 
tests to establish fully its arsenic character. 

Nitric acid, assisted by sulphuric acid, is sometimes used to 
destroy the organic matter and oxidize the arsenic into arsenic 
acid. In such a case the arsenic acid can be readily extracted by 
boiling water, and the solution filtered and evaporated to dryness. 
Marsh's test can be applied to the solution, and metallic arsenic 
will appear as a mirror on the tube or on cold porcelain. 

In order to estimate the arsenic the total quantity of fluid 



284 . THE METALS 

obtained, as above, from any organ, such as the liver, should be 
divided into equal parts, and one or more of these parts used to 
get a deposit of metallic arsenic in the heated tube by the Marsh- 
Berzelius method. The section of coated tube is cut off and 
weighed, and then washed free from arsenic with nitric acid or 
solution of sodium hypochlorite and weighed again. The differ- 
ence represents the amount of arsenic in the portion of the material 
used. The brown deposits, which are more or less transparent, 
consist of the suboxid, As 2 0, and hydrid, AsH 3 ; hence these quan- 
titative results can never be absolutely accurate. Another method 
of estimating is by converting the arsenic into sulphid. A meas- 
ured fraction of the dissolved materials, acidified with hydrochloric 
acid, is treated with a stream of pure, washed hydrogen suiphid gas. 
The yellow precipitate is collected on a filter, thoroughly washed, 
and then dissolved in ammonium hydroxid. By evaporating the 
solution thus obtained on a water-bath, the ammonia is removed 
and the dried sulphid, after treatment with carbon disulphid to 
dissolve out any free sulphur that may be present, is weighed, and 
the calculation made on the basis that 100 parts of the sulphid 
contain 60.98 of elementary arsenic. As arsenic acid and the 
arsenates are precipitated very slowly by hydrogen sulphid, they 
will require other treatment (see p. 286). 

When the amount of organic matter present is small, as in the 
urine, the test for arsenic can be got at by a more direct method. 
Concentrated sulphuric acid containing -3V its volume of nitric acid 
is added to the residue of urine, which has been evaporated to 
dryness over a water-bath, and the mixture is heated until dense 
white fumes 'are given off. The charred materials are extracted 
with boiling water, the solution concentrated over a water-bath, 
and introduced at once into the Marsh apparatus. 

Detection in Wall-paper. — When there is reason to think that 
the amount of arsenic is considerable, resort may be had to 
Reinsch's test. .Five square inches of the paper cut finely are 
put in a dish with dilute hydrochloric acid, and heated on a water- 
bath for fifteen minutes. The solution is then decanted into 
a test-tube, a piece of polished copper-foil added, and then boiled 
for ten minutes. The arsenic coating on the copper can be 
verified by the confirmatory tests given on p. 277. 

When the amount present is so small as to give a doubtful 
result to Reinsch's test, it may still be revealed by the Marsh- 
Berzelius method. The arsenic is dissolved from the paper as 
stated above, and the acid solution poured into the Marsh appa- 
ratus (Fig. 66). The blackness of the arsenic mirror formed in 
the glass tube, when compared with a series of standard arsenic 
mirrors, will give an approximation to the quantity. 



ARSENIC 285 

Distribution of Absorbed Arsenic. — Besides that which may 
be found in the contents of the stomach and intestines, a variable 
proportion of arsenic is absorbed, and by the blood and other 
fluids is distributed to different organs and tissues. This latter 
part has certainly had a poisonous effect, whatever may be said 
of that found unabsorbed. Even when none has been found in 
the contents or even the structure of the stomach and the intestines, 
the liver, kidneys, spleen, and heart have rendered up their store 
to the analyst. The muscular and bony tissues and the brain 
are also places for the deposit of absorbed arsenic. 

It not infrequently happens that the arsenic is taken in a very 
soluble form, and, the patient surviving for two weeks or even 
less, no poison can be detected in the viscera usually examined. 
This is due to the activity of the circulation in the soft tissues 
and the readiness with which the poison is eliminated. Under 
such circumstances, several observers have discovered the poison 
still present in the cancellated structure of the bones and in the 
nails and hair. Arsenic has been detected in the urine ninety- 
three days after a single large dose had been administered, causing 
acute symptoms and having a sequel of paralysis. 

Failure to Detect. — Instances are known of undoubted poisoning 
in which no trace of the arsenic has been found in the parts usually 
examined. The eliminating organs had time before death to 
expel the unnatural substance. 

Normal Arsenic. — Gautier found arsenic in the tissues of 
the thyroid and thymus glands, the skin, and the brain, chiefly in 
the form of nuclein iodid. Later he reported it constantly present 
in the fresh thyroid of man. A trace was found in the hair of a 
man and also of a woman, neither of whom had ever taken arsenic. 
Some was detected in the thymus of a lamb. Traces were dis- 
covered in the mammae of a cow and in two quarts of her milk. 
Fresh bone furnished a trace. The brains of two stillborn chil- 
dren showed its presence, but it was absent in a third. He failed 
to find arsenic in the presumably healthy tissue of liver, kidney, 
spleen, muscles, testicles, pituitary gland, mucous membrane, 
cellular tissue, lymphatics, salivary glands, suprarenal capsules, 
bone-marrow, uterus, ovaries, blood, urine, and feces. Upon 
examining various foods he found it absent from bread, fish, eggs, 
and meats, excepting the tissues named above — viz., milk, thymus, 
thyroid, skin, and brain. It was present in the following 
vegetables: cereals, turnips, cabbages, and potatoes. In case 
arsenic should be found in the tissues named above as nor- 
mally free from it, the inference would be that arsenic had been 
taken as a medicine or criminally. 

Measurable quantities of arsenic have been found in 1 gm. of 



2 86 THE METALS 

the hair of several persons having arsenic neuritis, and a trace 
has been detected in the same amount of hair from healthy sub- 
jects. 

Hodlmoser, W. Thomson, and also Wieser reach a conclusion 
opposed to that of Gautier. Their researches showed that arsenic 
is not a normal constituent of the human body, though it is often 
accidentally present in animal and human tissues. Not even 
a trace of arsenic was found in the liver and pancreas in 18 cases 
examined by Gautier's method, nor in 15 other cases in which 
the same viscera were examined by another process esteemed 
more delicate. In repeating the experiments of Gautier, referred 
to on different tissues, they always obtained negative results. 

Arsenic Pentoxid (As 3 5 ) (Arsenic Acid). — This commonly 
occurs in white, vitreous, deliquescent masses, but may be ob- 
tained as rhombic crystals. The pentoxid deliquesces in the air 
and changes to the true arsenic acid, As 2 5 + 3H 2 = 2H 3 As0 4 . 
This acid is produced immediately by oxidizing arsenic trioxid, 
when it is heated with nitric acid in the presence of water, As 2 3 + 
2 + 3H 2 = 2H 3 As0 4 . Like phosphoric acid (page 189), it is 
tribasic and forms three series of salts, according to the number of 
hydrogen atoms replaced. It also loses water in stages forming 
pyro- (H 4 As 2 7 ) and meta- (HAs0 3 ) acids like the corresponding 
forms of phosphoric acid. The ortho- or common arsenic acid 
is a colorless, syrupy liquid with a metallic taste. Like arsenic 
trioxid, it is an irritant poison. The free acid is not used in 
medicine, but some of its salts are. It is much used in the manu- 
facture of dyes, although recently other oxidizers have supplanted 
it to a considerable degree. It responds to the same tests as 
arsenic trioxid, but has a peculiar reaction with silver nitrate, 
forming a brick-red precipitate (Plate 2, No. 4). It will respond 
to Marsh's test, but it is precipitated very slowly by hydrogen 
sulphid. If there be reason to think that either arsenic acid or 
any arsenate is present in the tested fluid, it should be reduced 
to arsenous acid by a current of sulphur dioxid and the latter 
removed by passing carbon dioxid before the hydrogen sulphid 
is added to it. A solution of sodium arsenate, 4 lb. to 1 gal., 
is commonly injected by undertakers through the nostrils into 
the stomach and into the thoracic cavity in order to arrest decay 
in warm weather. Sometimes cloths are wet with it and wrapped 
about the corpse to accomplish the same end. 

Presence of Arsenic in Various Substances.— Medicinal 
Preparations. — The arseni trioxidum of the U. S. P. (white 
arsenic, As 2 O s ) is present to the amount of 1 per cent, in each of 
the following preparations: liquor acidi arsenosi in 5 per cent, 
dilute hydrochloric acid; liquor potasii arsenitis (Fowler's solu- 



ARSENIC 287 

tion); liquor sodii arsenitis (Harle's solution). Donovan's solu- 
tion, or liquor arseni et hydrargyri iodidi, contains 1 per cent, 
each of arsenous iodid, Asl 3 , and mercuric iodid, Hgl 2 , while 
Pearson's, or liquor sodii arsenates, contains 1 per cent, of exsic- 
cated sodium arsenate, Na 2 HAs0 4 , 7H 2 0. Sodii arsenas occurs 
as colorless, odorless prisms, soluble in water. Sodii arsenas 
exsiccatus is an amorphous white powder, permanent, very solu- 
ble and double the strength of the hydrous salt just mentioned. 
Arseni iodidum occurs as an orange-red crystalline powder, water- 
soluble with slight decomposition. Cacodyl, 2As(CH 3 ) 2 (dimethyl- 
arsin), is a volatile, colorless liquid with garlic odor and poisonous. 
Cacodylic acid, As(CH 3 ) 2 2 H, is a white crystalline substance, 
soluble, odorless, and comparatively non-poisonous, though it 
contains 54 per cent, of elementary arsenic. In overdoses it 
causes the same symptoms as arsenous acid. Sodium cacodylate, 
or sodium dimethyl arsenate, As(CH 3 ) 2 2 Na, a white soluble 
powder, while generally well borne in large doses (of 1 to 3 gr.), 
may undergo changes when given by the stomach or the rectum 
and have toxic effects. It contains arsenic in a complex organic 
group and very high proportion, but liberates the active arsenic 
ion in the body very slowly. It is eliminated in the urine as 
arsenates. The same can be said of atoxyl, C 6 H 4 (NH 2 ) (AsO. 
OH.ONa) (sodium aminophenyl arsenate), which is a white 
odorless powder, water-soluble, containing 26 per cent, of arsenic. 
A 20-per cent, solution is given hypodermically. Dose: f to 3 gr. 
(0.5 to 0.2 gm.) per day. Three grains contain J gr. arsenic (As). 
An arsenic paste has been applied to tumors by cancer quacks so 
unskilfully as to produce systemic poisoning by absorption. The 
manufacturers of gelatin-coated and sugar-coated pills sell large 
quantities of tonic pills containing arsenic as a constituent. It 
is often a contaminant of commercial glycerin and of subnitrate 
of bismuth. In 1 out of 8 samples of bismuth subnitrate examined 
arsenic was found; it was present to the amount of 0.33 per cent, 
of the element. In this preparation it probably exists as bismuth 
arsenate, a form not readily absorbed because of its insolubility. 

In Preservatives and Cleaners. — In order to* keep wheat for 
planting it has been treated with an arsenic solution which does 
not alter its appearance or taste. Samples so treated have caused 
accidental poisoning. A mixture of white arsenic, tar, and soft 
soap is sometimes used as a " sheep dip" to destroy the parasites 
in wool. The sheep-washers have experienced poisonous effects 
from handling it and from drinking water from a vessel that once 
contained it. Taxidermists make use of an arsenic soap and an 
arsenic powder to preserve skins. The workmen have suffered, 
and it is stated that poisonous symptoms can be traced to the 



288 THE METALS 

arsenic emanating from stuffed specimens kept in sleeping-rooms. 
Wholesale poisoning has followed the introduction into a boiler 
of a " cleaner" made from arsenic and sodium bicarbonate. A 
similar solution has been used as a "soft injection" or preservative 
of bodies for dissection. Dissectors handling the bodies are likely 
to have a local irritation about the finger-nails. 

In Anilin Dyes. — Arsenic acid or arsenic pentoxid is frequently 
used as an oxidizer by the color-men in the preparation of anilin 
red and other- pigments. It is not a necessary ingredient of the 
pigment, and at this time is not so often found in it as formerly. 
The expense of washing out this residuum still sometimes deters 
the manufacturers, and the dye may come into the market with 
enough arsenic in it to give irritant properties to stockings, gloves, 
and cretonne bed-trimmings reddened with it. This impure 
anilin red has been used to color strawberry and raspberry 
syrups. 

In the Air.— In the chemical laboratories 8 deaths have 
occurred from the accidental inhalation of the vapor of arsenureted 
hydrogen escaped from the Marsh apparatus. It has destroyed 
life in quantities so small as not. to impart a garlicky odor to the 
air. Traces of this poison have been found in common illumi- 
nating gas. By some writers this is the form supposed to be taken 
by the arsenic emanations of wall-paper, though other authorities 
suppose the emanation to be an organic compound, such as cacodyl 
oxid. In the extraction of gold and silver from certain ores, the 
cleaning of iron for tinning and of brass for bronzing, acids are 
used which liberate hydrogen. This nascent hydrogen unites with 
arsenic impurities in the ores or the metal, if any be present, and 
thus poisons the air breathed by the workmen. 

In Beer. — The glucose used in brewing sometimes contains 
arsenic. It is left in the glucose by the sulphuric acid employed 
in the conversion from starch when the acid is obtained from 
arsenic iron pyrites. Extensive poisoning occurred in the Mid- 
land counties of England attributed to arsenic in beer, and ex- 
tended through six months. The most frequent characteristic 
symptoms were catarrh, pumness of the eyelids, irregular pigmen- 
tation of the skin, herpes, and other eruptions, local numbness, 
tingling, and pain, with final paralysis. Arsenic was detected 
in the urine and in the hair. The amount of arsenic found in 
different samples of beer varied from yto to y%- gr. to the gallon. 

In the Household. — Many cases of poisoning, accidental or 
otherwise, have been traced to things in common domestic use. 
"Fly-papers" for killing flies are sheets of paper saturated with 
sweet solutions or pastes of arsenic. Single sheets have been 
examined which contained 10 gr. of arsenic trioxid available 






ARSENIC 289 

for the poisoner. " Fly-powders " have been made by pulverizing 
the mineral arsenid of cobalt. "Buffalo Carpet-moth Annihil- 
ator," intended to be dusted over the carpet, is a powder con- 
taining arsenic. White arsenic is often mixed with a dough of 
flour or cornmeal and distributed in cellars and pantries to kill 
mice. The most extensively used domestic vermin-killer is 
"Rough on Rats," a mixture of white arsenic with charcoal. It is 
a gray powder put up in packages and procurable in every drug- 
store without restraint or legal registration. In this country a large 
number of suicides and some homicides have been caused by this 
agent. Among the means for wilful death it appears to be our 
national favorite. It is cheap, knowledge of its deadly properties 
is common, and there is every facility for purchasing it under the 
excuse of killing vermin. It is much to be desired that our State 
and Municipal legislation relative to the sale of arsenic commodi- 
ties should be shaped after the pattern of other civilized countries. 
Some provision should be made in the laws of every State which 
would require apothecaries to keep an arsenic book for recording 
sales of this poison, and which would forbid the sale of arsenic 
in any shape for the purpose of destroying vermin or for the 
embalming of dead bodies. 

To overcome the gypsy moth the white precipitate of lead 
arsenate, Pb 3 2As0 4 , is applied to the foliage of plants. "Arsenic 
balls" are given by grooms to improve the coats of horses. Some 
kinds of white enamel-ware and some glass contain arsenic. 
It has been found in the silk lining of coat cleeves, the glazed 
leather lining of hats, the brown paper lining of carpets, and the 
black cambric lining of furniture. It is sometimes present on the 
glazed paper and cardboard used for boxes, playing-cards, note- 
paper, and fancy wrappers for candy lozenges. At one time 
arsenic pigments were extensively used for coloring wall-hangings, 
lambrequins, cretonnes, chintzes, tarlatans, and artificial flowers 
and leaves. It has been alleged that numerous cases of slow 
poisoning have been traced to the arsenic from these sources 
pervading the atmosphere of dwellings. In making a diagnosis 
reliance has been placed upon the discovery of traces of arsenic 
in the urine of patients. It has been found there with surprising 
frequency. 

Traces of arsenic, copper, and mercury have been detected in 
the urine of numerous healthy individuals examined. These sub- 
stances are not totally eliminated by the organism, and in time 
the accumulated amounts from domestic sources might have an 
important bearing in certain medicolegal cases. 

A volatile arsenic compound, probably an organic derivative 
of arsenic pentoxid, is produced by certain common moulds 
19 



2QO THE METALS 

growing in contact with arsenicated substances such as might be 
used in wall-papers. 

In the present state of knowledge no wall-paper containing as 
much as o.i gr. of arsenic in a square yard can be considered as 
harmless. 

In Common Pigments. — Both accidental and intentional 
poisoning occur from the use of the pigments described below: 

Scheele's green (copper arsenite, CuHAs0 3 ) contains 52.8 per 
cent, of arsenous acid. A bright green paint is made by mixing 
this with the basis of oil-paints and of water-colors. Although 
the public is warned as to the deadly character of this pigment 
it is still much used for giving color to wax tapers, toys, book- 
covers, artificial flowers, oilcloth, calicoes, cretonnes, and tar- 
latan. An equivalent green color and one much less injurious 
can be made by mixing Prussian blue and chrome yellow. 

Paris green (copper aceto-arsenite, Schweinfurth green) is a 
color made by mixing the acetate of copper with the arsenite. 
It contains over 50 per cent, of arsenic. There is an enormous 
consumption of this compound as an application to the potato 
plant to rid it of the Colorado beetle. Used on the tops, this does 
not affect the edible tuber under ground. The same practice 
upon the tobacco-plant is far from innocent, as the leaves here are 
the parts to be used. It is often taken by suicides, but its color 
usually prevents its criminal use, though occasionally accidental 
death has been caused by it. 

Arsenic trisulphid (As 2 S 3 ) (orpiment, King's yellow), containing 
61 per cent, of arsenic, is a yellow powder precipitated from acid 
solutions of arsenic by hydrogen sulphid. By mistake it has 
sometimes been substituted for the harmless vegetable pigment, 
turmeric. The action is similar to that of white arsenic. Arsenic 
trisulphid is insoluble in water and acids, but soluble in the alkalis 
and their carbonates, and in soluble sulphids and hydrosulphids. 
When precipitated with other metals from acid solution by hydro- 
gen sulphid, it can be separated from all other sulphids by means 
of its solubility in ammonium carbonate. 

When a dilute solution of arsenous acid is treated with hydro- 
gen sulphid, the solution turns yellow without precipitation. Its 
effects on transmitted light show that the arsenic trisulphid is not 
in solution, but is suspended in particles too small to be stopped 
by filter-paper or to be seen with a microscope. If small quanti- 
ties of solutions of electrolytes such as acids and ordinary neutral 
salts are added, the sulphid separates in visible flakes. These 
properties are characteristic of the class of colloidal solutions. 
Upon them the coagulative powers of different solutions of elec- 
trolytes vary according to the valency of one of the ions and the 



ANTIMONY 291 

equivalent conductivities for electricity. It seems probable 
that coagulation depends on the action of the electric charges 
received by the drifting ions of the electrolytes. The colloid par- 
ticles appear to exist in solution only when charged electrically. 
Collision with the mobile ions of the electrolyte neutralizes them, 
they form larger aggregates, and precipitation follows. 

Arsenic disulphid, As 2 S 2 , realgar, occurs in ruby-red crystals 
containing 70 per cent, of arsenic. It can be made by fusing sul- 
phur and arsenic together. It dissolves in alkalis and their car- 
bonates. 

Arsenic in the Soil. — Some soils naturally contain arsenic in an 
insoluble iron compound. This compound is incapable of yielding 
arsenic to a corpse buried in it. It has been stated above that 
arsenic is frequently present in commercial sulphuric acid. This 
acid is used in the manufacture of superphosphate and other arti- 
ficial manures, which contribute it to the soil. From the soil it 
may be taken by our food-plants, such as potatoes and turnips. 
In cities it is the general custom for undertakers to embalm corpses 
by pumping a solution of sodium arsenate through the nostrils 
into the stomach, trusting to the high diffusibility of that salt 
to carry it throughout the body. Experiments show that in 
twelve days the arsenic may permeate the entire body, reaching 
the brain. It is possible that this same compound would event- 
ually pervade the soil of the cemetery contiguous to a buried corpse. 

ANTIMONY (Stibium) 

Symbol, Sb. Atomic weight, 120. 

Antimony is a brilliant gray-white solid with a crystalline, 
metallic fracture, tasteless and odorless. When heated it volatil- 
izes; at a higher temperature it burns to white fumes of antimony 
trioxid, Sb 2 O s . It is used as an alloy in type metal, Britannia 
metal, brass, and bell metal. Though the metal may not be 
poisonous, its salts are. 

While poisoning from antimony was quite common in the Middle 
Ages, in our times it is comparatively rare. Cases have been 
reported from inhalation, probably of the trioxid, in certain indus- 
tries. Lozenges containing the same preparation were the cause 
of poisoning in another case. In modern toxicology but two 
forms figure to any extent, the trichlorid and tartar emetic. 

Sulphurated antimony (Kermes mineral), a mixture of 
Sb 2 S 3 and Sb 2 O s , is employed in vulcanizing rubber. The India 
rubber connections of the Marsh apparatus might thus contribute 
a trace of antimony, unless care be taken to avoid the use of 
fittings made with this preparation. It is a constituent of the 
medical preparation, Plummer 's pill. 



292 THE METALS 

Antimony trioxid, Sb 2 3 , occurs as a white powder of basic 
properties, although, because it corresponds to As 2 O s , it is some- 
times erroneously called antimonious acid. It dissolves in alkalies; 
hence, undergoes some change and possibly forms an anion, as in 
the formula H>, (Sb0 2 ); thus, sodium meta-antimoniate is NaSb0 2 . 
Dose: 1 to 3 gr. (0.06-0.2 gm.). It is a component of James 1 
powder, which contains calcium phosphate with antimony trioxid. 

Antimony terhydrid (SbH 3 ) (antimoniureted hydrogen) is 
a colorless, odorless gas, corresponding to arsenic terhydrid. It 
is given off when zinc and sulphuric acid react in the presence of 
an antimony salt. It differs from arsenic terhydrid in having no 
garlicky odor and in being less poisonous. 

Antimony trichlorid (SbCl 3 ) {butter oj antimony) occurs as 
a soft solid. A strong solution of the chlorid in hydrochloric acid 
is employed in the arts as a bronzing liquid and in farriery. It 
crystallizes white and transparent. Added to water, a whitish 
precipitate falls, of antimonyl chlorid, SbOCl. 

The records of 8 cases of poisoning show that in the 4 fatal 
ones the dose was 2 oz., while 2 that recovered took 1 oz. each. 
A woman of forty years died in less than two hours; in her stomach 
were found 8 gr. of antimony and 0.1 gr. of arsenic. 

Tartar Emetic (KSbOC 4 H 4 6 ) (Tartar ated Antimony, Stib- 
iated Tartar, Antimonii et Potassii Tartras). — This is a white 
crystalline powder with an acrid, disagreeable, metallic taste. It 
is made by the action of a boiling solution of cream of tartar 
upon antimony trioxid. Dose: J to 3 gr. (0.008-0.2 gm.). It 
may be regarded as acid tartrate of potassium, KHC 4 H 4 6 , the 
hydrogen of which is replaced by the radical antimonyl SbO. It 
has been dispensed by mistake for cream of tartar and for tartaric 
acid. It is soluble in cold water, more readily in hot water, but 
insoluble in alcohol. Wine is used as a vehicle in vinum anti- 
monii (0.4 per cent, tartar emetic), the water of the wine acting 
as a solvent and the alcohol checking the formation of the moulds, 
to which a simple aqueous solution is liable. It is present in 
syrupus scillce compositus ("Hive Syrup"), dose: 15 to 60 1TL 
(1-3 c.c), and in unguentum antimonii. 

Symptoms. — There is a close resemblance between the symp- 
toms caused by antimony and those produced by arsenic. While 
it occasionally happens that large doses (200 gr. of tartar emetic) 
do not cause vomiting, as a rule, nausea, retching, and vomiting 
come on within half an hour and continue as conspicuous features 
of the clinical picture, which may be sketched as follows: In a 
few seconds there is an acrid and metallic taste, followed by a sense 
of constriction in the throat and pain in the stomach; frequent and 
profuse vomiting, sometimes of bloody material; diarrhea with 



ANTIMONY 293 

watery discharges, sometimes involuntary, sometimes attended 
with tenesmus; fainting attacks and depression, characterized by 
a feeble and frequent pulse and profuse sweating; spasmodic con- 
traction of the arms, fingers, and legs. In very grave cases the 
urine may be wholly suppressed, the temperature subnormal, the 
skin cyanotic, and death be ushered in by delirium, convulsions, 
and coma. There are exceptional cases in which no vomiting 
occurs for an hour, and others in which drowsiness and power- 
lessness come on early, are succeeded by tetanic spasms, the other 
symptoms also being present, and later, persistent enteritis with 
loss of the hair on recovery. In 1 case coma was the prominent 
symptom, with death on the sixth day. 

When antimony chlorid has been taken, to the symptoms of 
antimony-poisoning are added those of the strongly acid liquid, 
which causes corrosion of the stomach. 

Chronic Poisoning. — In most cases of homicidal poisoning 
from antimony, tartar emetic has been given in divided doses to 
invalids. The effects of the poison are thus mistaken for symp- 
toms of some low fever or chronic disease, and the crime may go 
undetected. The patient is seen to suffer from "sickness," 
loathing for food, which, if taken, is not retained, diarrhea, mus- 
cular cramps, physical and nervous prostration, weak pulse, and 
cold sweats. 

Fatal Dose of Tartar Emetic. — The smallest dose that has 
proved fatal to a child is f gr. (48.5 mg.). A healthy woman, aged 
twenty-five years, took the maximum medicinal dose, ij gr. 
(97.2 mg.), without effect, but a similar dose twenty-four hours 
later excited violent purging and vomiting, with death in thirty- 
six hours. Such cases cannot be considered as fixing the danger 
limit. Ten grains at one time would be a dangerous dose, but 
the same amount in broken doses would be still more so. 

Recovery has followed a dose of 170 gr. As a rule, prompt 
emesis follows the administration of a large dose, and the effects 
are mainly local and not serious. If the poison be retained and 
absorbed, the vomiting center is indirectly involved, and purging, 
with extreme depression, becomes the prominent symptom. At 
one time it was considered good practice in acute inflammatory 
diseases to give doses of 1 gr. at intervals, to establish " tolerance." 
By the second day some patients would tolerate the drug without 
vomiting and purging; and "heroic" doses of 5 gr. each could be 
given without inducing these effects. As much as 60 gr. daily 
have been given in this way without disturbance of the stomach. 
The effects in such cases are mainly those of depression of the 
heart action and of the nervous system. 

Fatal Period. — A fatal result has occurred in an adult in seven 



294 THE METALS 

hours. In an exceptional case death occurred in a child in three- 
quarters of an hour. The fatal event may be delayed for several 
days, the average duration of life being twenty-four hours. 

Treatment. — As a rule, the free vomiting induced by the tartar 
emetic is sufficient to evacuate the stomach. In the rare cases 
where it does not occur, other emetics should be given, such as 
sulphate of zinc or mustard and water; or the stomach may be 
washed out with a mixture of hot water with the antidote, tannic 
acid; or a decoction of green tea or of some vegetable astringent 
— all these forming the insoluble tannate of antimony. When 
the stomach has been emptied morphin should be given hypo- 
dermically to relieve pain, and the irritable stomach and bowels 
treated with suitable remedies. The depression of the heart must 
be counteracted with stimulants, aided by dry heat or mustard to 
the epigastrium and the extremities. 

If antimony chlorid has been taken, the corrosive action on the 
stomach would cause a condition which would be aggravated by 
the mechanical irritation of the stomach-tube. 

Postmortem Appearances. — In i case of acute tartar-emetic 
poisoning the autopsy revealed nothing, although the poison was 
found in the viscera, urine, blood, and intestinal contents. Such 
a result is quite exceptional, most cases showing redness, swell- 
ing, ecchymotic patches, and perhaps ulceration in the gastro- 
intestinal mucous membrane. Sometimes the changes in the gullet 
and pharynx are profound, as in a case in which there was de- 
structive ulceration of the membrane of the epiglottis and of the 
adjacent parts, exposing the muscular fibers of the pharynx. In 
a case of poisoning from the corrosive antimony chlorid, after 
vomiting without blood, the patient went into collapse and died in 
two hours. The gastric membrane was almost black from con- 
gestion. 

In cases of chronic poisoning it is usual to find inflammation 
of the kidneys and liver. 

When heated in a test-tube tartar emetic chars, and later gives 
an amorphous sublimate of Sb 2 3 . 

Tests. — Hydrogen Sulphid. — A stream of this gas will precipi- 
tate orange-red antimony trisulphid, Sb 2 S 3 , when passed through 
any antimonial aqueous solution acidified with hydrochloric acid 
(Plate 2, No. 5). This orange precipitate is insoluble in ammo- 
nium hydroxid, but dissolves in the fixed alkalis, in ammonium 
sulphid, and in strong hydrochloric acid, especially when heated. 
A very characteristic reaction is obtained when this hydrochloric 
acid solution (after boiling to expel all trace of hydrogen sulphid) 
is diluted with excess of water. A white precipitate of antimony 
oxychlorid falls, which is soluble in tartaric acid. 



ANTIMONY 295 

Fallacies. — While this test is quite certain in simple solution, 
it may give a doubtful result in the presence of colored organic 
materials. These should be entirely destroyed to give a satis- 
factory verdict. 

Delicacy. — A definite reaction can be obtained with 10000 of 
a grain of antimony trioxid in 5 gr. of solution. 

Reinsch's Test. — The method of performing this test has been 
described in another place (p. 277). If any precipitate form, 
when the suspected solution is acidified with hydrochloric acid, 
more acid must be added until the oxychlorid is redissolved. On 
boiling in it a strip of bright, pure copper-foil a film of metallic 
antimony will appear. If the amount be small, the film is violet. 
A larger quantity will give a surface like tarnished zinc, and, if 
abundant, a black amorphous layer. 

Fallacies. — Arsenic, mercury, and some other metals make 
similar deposits. To distinguish the nature of the metallic films 
the copper strip must be washed in water, alcohol, and ether, 
dried, coiled, and heated in a glass tube open at both ends. Under 
this treatment antimony yields a white sublimate of antimony tri- 
oxid which is usually amorphous, although sometimes showing 
crystals; arsenic gives a sublimate of octahedral crystals; mer- 
cury a sublimate of shining metallic globules; and other metals, 
as a rule, produce no sublimate. The antimony trioxid may be 
dissolved in weak tartaric acid and an orange-red precipitate be 
obtained by passing hydrogen sulphid after acidification with 
hydrochloric acid. Again, the film of antimony on copper may 
be identified by boiling it in a weak solution of potassium hydroxid, 
removing the strip at intervals to expose it to the air. If the 
solution of antimony thus made is acidified with hydrochloric 
acid, it will yield an orange-red precipitate with hydrogen sulphid. 

Delicacy. — A distinct violet-colored deposit on the copper can 
be obtained from 1 gr. of a solution containing 20000 g r - of tartar 
emetic, or 50000 gr. of antimony trioxid. 

Marsh's Test. — In the section on Arsenic (p. 279) details are 
given for performing this test. If antimony be present the gas- 
eous terhydrid will be formed which has not the onion-like odor 
of arsenic terhydrid. Its flame produces a black spot on cold 
porcelain, while a metallic mirror forms in the delivery tube if 
that be heated by Berzelius' method. These may be mistaken 
for the similar deposits made by arsenic. When treated with 
solution of chlorinated lime or chlorinated soda the antimony 
deposit is insoluble, while arsenic dissolves. Yellow ammonium 
sulphid dissolves both, but on evaporation the solution of anti- 
mony sulphid leaves an orange-red spot soluble in strong hydro- 
chloric acid, but insoluble in ammonia. The corresponding 



296 THE METALS 

arsenic sulphid is yellow, insoluble in hydrochloric acid, but 
soluble in ammonia. 

If the gas, instead of being burned or decomposed by heat as 
above, be passed into solution of silver nitrate, there is a black 
deposit of silver antimonid, Ag 3 Sb. If arsenic be also present, it 
remains in solution and, by nitration, we can separate the two. 
The filtrate can be tested for arsenic. The antimony in the pre- 
cipitate may be separated from the silver by dissolving in boiling, 
weak hydrochloric acid. When filtered again and treated with 
hydrogen sulphid the filtrate gives orange-red antimony sulphid. 

Delicacy. — With a small apparatus spots on porcelain are 
obtained from 50 gr. of a fluid containing -^s gr- of antimony 
trioxid, while a good deposit in the heated tube is yielded by the 
same amount of fluid containing twoo g r - of antimony trioxid. 

The silver nitrate test gives a still more delicate reaction, and 
can be obtained with only a few drops of the test solution, a satis- 
factory deposit of silver antimonid forming when there is present 
only g-^o 0" g r - °f tartar emetic, equal to tuwo gr. of antimony trioxid. 

Zinc Test. — The suspected liquid is put into a platirium dish 
and acidified with hydrochloric acid. On immersing a slip of 
pure zinc the antimony, but not arsenic, is at once deposited on 
the platinum as a black stain, which can be removed later by 
nitric acid or by simple heat. The true nature of this stain is 
revealed by wetting it with nitric acid, drying at a gentle heat, 
and touching with a drop of dilute ammonium sulphid, when an 
orange-red color will be produced, due to the formation of anti- 
mony trisulphid. 

Delicacy. — This test is very delicate. In two minutes a brown 
stain will appear when the solution holds but 10000 gr. of anti- 
mony, a definite reaction showing in a quarter of an hour when 
the amount is only 2 oooo - 

Tin Test. — If an antimony solution be acidulated with yo part 
hydrochloric acid and a slip of pure tinfoil is immersed in it, the 
foil turns black from a deposit of metallic antimony. 

Detection.— In Vomited Matters and Urine.— Owing to the 
prompt action of tartar emetic, the stomach and bowels are usually 
quickly evacuated of the poison. A large part of that which 
is absorbed into the general circulation is rapidly eliminated 
by the kidneys, and hence the proportion stored in the viscera is 
relatively small. In cases of suspected chronic poisoning the 
vomited matters, the liquid feces, the urine, or medicinal mixtures 
should be subjected to analysis. For this purpose the material 
is acidified with hydrochloric acid, and the zinc test or Reinsch's 
test applied. These respond even in the presence of organic 
matter. To another portion of the material, acidified with hydro- 



ANTIMONY 297 

chloric acid, tartaric acid is added; it is heated on a water-bath 
for half an hour, strained, filtered, and the filtrate treated with 
a stream of hydrogen sulphid for several hours. The precipitate, 
which may contain the sulphids of certain other metals and free 
sulphur, should be treated with strong hydrochloric acid and 
boiled as long as hydrogen sulphid fumes escape. The filtered 
solution may be tested with Reinsch's test, the zinc test, or Marsh's 
test, collecting the antimony in silver nitrate solution. In testing 
the urine the total quantity for several days should be evaporated 
to a small bulk before being operated on. 

Separation from the Tissues. — From the solid viscera most of 
the antimony can be extracted by mincing a portion and boiling 
it for an hour in water, 5 parts, acidified with hydrochloric acid, 
1 part. The strained and filtered solution may be tested by 
Reinsch's or the zinc test. 

Quantitative Determination.— If it be desired to calculate 
the total amount of antimony, it is best to use the process for 
destruction of organic matter by hydrochloric acid and potassium 
chlorate given in another place (p. 283). This being done, 
the mixed precipitate obtained by passing hydrogen sulphid 
through the acidified fluid is washed, treated with strong nitric 
acid, and evaporated to dryness. A small quantity of a strong 
solution of potassium hydroxid is added to the residue, it is fil- 
tered, evaporated to dryness, and fused. The potassium anti- 
monate in this fluid is boiled with solution of tartaric acid, acidu- 
lated with hydrochloric acid, filtered, and saturated with hydrogen 
sulphid gas. The orange-red antimonic sulphid, Sb 2 S 5 , thus ob- 
tained is washed on a Gooch filter, 1 
dried in a water oven, and the free sul- 
phur and residual moisture which are 
always present expelled by heating in an 
atmosphere of dry carbon dioxid. Of 
this residue, which has been converted 
to black sulphid, Sb,S 3 , 100 parts rep- 
resent 71.77 of antimony. 

When the presence of other poison- 
ous metals is suspected the precipitate 
made with hydrogen sulphid is treated 

thoroughly with yellow ammonium fig. 68.-Gooch niter or funnel, 
sulphid and the solution filtered. The 

arsenic or antimony is present in this filtrate, while mercury, 
lead, and copper remain upon the filter to be examined by 

1 A Gooch filter is one in which filtration is effected through an inner lining of 
asbestos felt, which has been introduced into the perforated bottom of a platinum 
or porcelain crucible. The precipitate, filtered and washed in the usual way, may 
be dried and ignited without being removed from the crucible. 




298 THE METALS 

appropriate methods. The filtrate is evaporated, and the resi- 
due treated with nitric acid and potassium hydroxid to convert 
the metals into potassium arsenate and antimonate. If the 
presence of both metals be suspected, this mixture is put into 
the sulphuric acid and zinc Marsh apparatus, and the gas passed 
through silver nitrate as long as a black precipitate falls. The 
arsenic will be in the solution, and is separated by filtration. The 
black antimonid of silver is collected on a filter, washed, boiled 
with tartaric acid, acidulated with hydrochloric acid, filtered, and 
the filtrate precipitated with hydrogen sulphid. Of the dried 
precipitate of orange sulphid, 100 parts represent 196.47 parts of 
pure crystallized tartar emetic. 



TIN (Stannum) 
Symbol, Sn. Atomic weight, 118.8. 

The commercial metal is obtained from tin stone, Sn0 2 , by 
reduction with coal. It is a silver- white metal, melting at 228 C. 
(440 ° F.), and does not tarnish in the air. It is used as pure 
block tin; in tin-plate, sheets of iron coated with thin layers of tin; 
tinfoil, thin leaves sometimes containing lead; tin amalgam, silver 
coating for mirrors. It resists the action of air and water so well 
that vessels coated with it are universally used in the household. 
It is present in many forms of bronze as alloys with copper, in 
Britannia metal, alloyed with antimony, and in soft solder, alloyed 
with lead. 

Tin forms two series of compounds which are examples of its 
divalence and tetravalence. The first series are compounds of 
distannion, Sn", which is colorless and poisonous. They are 
called stannous, as that formed by the action of hydrochloric acid 
on tin, stannous chlorid, SnCl 2 . This is a strong deoxidizing 
agent, tending to pass over into the stannic condition, taking two 
more electric charges, and reducing arsenic, mercury, and gold 
salts to the metallic state. Dyers use it in calico printing. To 
check the tendency to become turbid, its solutions are kept stan- 
nous by a piece of metallic tin kept in the bottle. It makes a 
clear solution with one-third volume of water, but turns to white 
hydroxid, Sn(OH) 2 , with more water unless HC1 is added. On 
standing it absorbs oxygen and deposits the white oxychlorid. 
Stannic chlorid, SnCl 4 , contains tetrastannion, Sn**", which is the 
more stable ion. It is a fuming yellow liquid which tends to 
gelatinize by forming the hydroxid, Sn(OH) 4 . It is formed by 
the action of nitromuriatic acid on tin, or of free chlorin on stan- 
nous chlorid. With a molecule of free chlorin the cation takes 



TIN 



299 



up more positive electricity, the atoms of chlorin becoming 
ionized. 

Sn", CI', CI' + Cl 2 = Sn—, CI', CI', CI', CI'. 

Toxicology. — Though poisoning from tin salts is rarely re- 
ported, there is sufficient evidence to prove that it does occur. 

Putty powder, a higher oxid of tin, was the cause of death in 
the case of a chemist who, by mistake, used it for months in his 
pepper-box. The solder used for fruit-cans contains tin with lead. 
This, as well as the tin surface, may be dissolved by the action of 
acid juices of fruits or the fatty acids of meat and cause toxic 
symptoms. In the case of canned meats the danger from this 
source is slight, as the compound usually formed is insoluble in 
the digestive juices. The traces found in canned meat and fish 
exist as oxid, though in rare cases it is a basic stannous chlorid 
and sometimes a sulphid. The corrosion of the tin may increase 
slightly after the second year, but the amount is never anything 
but slight, even after four years. 

Symptoms. — Tin salts act as gastro-intestinal irritants, causing 
sometimes a metallic taste, usually nausea, vomiting, abdom- 
inal pain, diarrhea, cyanosis, and collapse. Severe symptoms like 
these were seen in 4 cases, due to eating tinned cherries, the 
strongly acid juice in the can showing 3.2 gr. of malate of tin 
to the fluidounce. 

In an investigation upon the lower animals it was shown that 
even the non-irritating salts given subcutaneously, caused toxic 
symptoms like those of other metals which undermine the health, 
sometimes even causing death. Tin was found in the tissues and 
the urine. Motor and sensory disturbances were noted in the 
lower extremities of a young woman whose skin was at the same 
period stained yellow from wearing yellow silk stockings. More 
marked nervous symptoms, like ataxia, were noted a few weeks 
later, simultaneously with wearing the stockings. The urine was 
albuminous, and gave the tin reaction for two months after the 
stockings had been laid aside. The stockings were heavily im- 
pregnated with tin chlorid to give them "body," and the absorbed 
tin had produced marked anemia. With the exception of hysteric 
symptoms, the patient recovered in a few months. 

Treatment. — Emetics and the stomach-pump should be used 
first, followed by eggs, bland demulcent drinks, stimulants, and 
anodynes. 

Tests. — Hydrogen sulphid yields with stannous solutions 
brown stannous sulphid, SnS, with stannic solutions, yellow stannic 
sulphid, SnS 2 (Plate 2, No. 6). Both precipitates are soluble in 
ammonium sulphid. 



300 THE METALS 

Mercuric chlorid is reduced by stannous chlorid to a gray 
deposit of metallic mercury. The reduction takes place in two 
stages. At first a white precipitate falls of mercurous chlorid 
and later this is reduced to the metallic state. 

HgCl 2 + SnCl 2 Hg + SnCl 4 . 

Solutions of fixed alkalis give with stannous salts a white 
precipitate of hydroxid, Sn(OH) 2 , which is dissolved by excess, and 
on boiling is reprecipitated as black oxid. With stannic salts the 
white precipitate is stannic acid, H 2 Sn0 3 , and when dissolved is 
not reprecipitated by boiling. 

Detection. — To extract the metal from the tissues and organic 
fluids they should be boiled for some time in water acidulated with 
hydrochloric acid, filtered, and the above tests applied to the filtrate.. 



V.— THE COPPER GROUP 

Copper, mercury, lead, bismuth, silver, and cadmium belong 
to a group of heavy metals whose sulphids are insoluble in water,, 
dilute acids, or ammonium sulphid. 

COPPER (Cuprum) 
Symbol, Cu. Atomic weight, 63.6. 

Occurrence. — Copper is found in the free condition; as cuprite 
or oxid; azurite and malachite, the blue and green carbonates; 
and as copper pyrites, CuFeS 2 . By processes of roasting and 
reduction the metal is obtained from these ores and finally puri- 
fied by electrolysis in a bath of its sulphate, using impure copper 
as an anode. 

Wide Distribution in Nature. — Not only is copper to be found 
in native masses and in its ores, but in minute proportions it is a 
constituent of many common minerals and soils. Natural water 
takes up a trace, and vegetation thus derives it from soil and from 
water. Careful analysis has detected it in edible roots, such as 
the turnip, in fruits, berries, salads, wheat, barley, and other cereals, 
coffee, chocolate, and quinin. From plants as food it is found to 
be derived by animals — domestic and wild. Even oysters some- 
times show a trace. Constantly present in our chief foods, it is not 
surprising that it is found in the body of man. Leaving out 
of the count foods possibly contaminated artificially, it is esti- 
mated that each of us takes daily about 1 mg. (0.015 gr.) of cop- 



COPPER 



3d 



per. At the same time it is not a physiologic constituent of the 
body, like iron. 

Physical Properties.— Copper is a heavy, bright-red solid 
which in moist air becomes coated with a green carbonate. It 
soon loses its red luster, taking a brown coat of oxidor sulphid. 
When heated it oxidizes in air to form a black oxid. Copper is 
of value in the arts because it is strong, malleable, ductile, a good 
conductor of electricity, and a resistant to most reagents, under 
ordinary conditions. 

Brass is an alloy of about 2 parts copper to 1 of zinc. 

Bronzes contain copper, tin, and sometimes zinc. 

Bell metal is an alloy of copper and tin. 

Phosphorus bronze is a copper bronze containing phosphorus. 

Aluminium bronze, which is yellow and resembles gold in 
appearance, is an alloy of copper and 8 per cent, aluminium. 

German silver is an alloy of copper, nickel, and zinc. 

Coin silver contains 10 per cent, of copper. 

Copper dissolves in nitric acid, in hot sulphuric acid, and, when 
exposed to the air, in hydrochloric acid and in ammonia. Even 
distilled water will in time take up some. One hundred cubic 
centimeters may dissolve 0.3 mg. of copper or 0.2 gr. in 1 gal. 
Water kept a few hours in a brightly polished copper vessel takes 
up the metal as colloidal solution in amounts harmless to man, but 
distinctly bactericidal. Natural waters containing salts, especially 
the chlorids, exert still more solvent powers. The syrups and fats 
dissolve it, and the fatty acids readily combine with it. Vinegar, 
acid wines, and subacid fruits kept for a few hours in copper 
vessels are found to contain the metal. 

The Ions of Copper. — Two series of copper salts are known, 
called respectively cuprous and cupric. In the cuprous salts the 
ion is univalent, monocuprion, Cw ; in the cupric it is bivalent, 
dicuprion, Cu". The latter condition is the more stable, and is 
characterized by the blue color of its salts. It is not poisonous, 
but some of its salts are irritants in large doses. 

When a piece of zinc is immersed in a copper sulphate solution 
the copper ion Cu** yields its two charges to an atom of zinc and 
is deposited as an atom; the zinc taking the charges passes from 
the atomic to the ion state as zinc sulphate in solution. 

Cu", (S0 4 )" + Zn = Zn", (SO,)" + Cu. 

This is the second mode of ion formation, which consists in a 
simple transference of electricity from metal to metal. 

Electrolytic Solution Tension. — A metal immersed in an aqueous 
solution exerts a pressure which tends to send off ions from the 



302 THE METALS 

metal into the solution. This solution tension is high with zinc, 
which has a great tendency to ionize, but lower with copper, which, 
therefore, gives place to the zinc. It is a general principle that 
metals with great solution-tension precipitate from their salts those 
that have less. 

Oxids. — The two ions are represented in the oxids: cuprous, 
Cu 2 0, and cupric, CuO. 

Cuprous oxid is the red powder precipitated in Trommer's test 
for glucose. A hot alkaline solution of a cupric salt is reduced 
red by the sugar in simple solutions, but in urine the precipitate 
is yellow or yellowish red (Plate 8, Fig. 3). 

Cupric oxid is the black coating formed on metallic copper when 
heated to dull redness in oxygen or air. If the oxid be heated, 
to a higher degree in the presence of hydrogen it gives up th& 
oxygen to form water. 

Cupric Hydroxid (Cu(HO) 2 ). — When a copper salt is acted 
upon by an alkaline hydroxid, a light blue precipitate is formed. 
It remains insoluble in potassium and sodium hydroxids, but in an 
excess of ammonium hydroxid it passes into solution with a deep, 
sapphire-blue color. A new ion, cuprammonium, Cu(NH 3 ) 4 ", 
has been produced, in which ammonia as a constituent persists, 
even when the salt has been separated as a dark blue solid. In 
performing Trommer's test without glucose, the addition of potas- 
sium hydroxid precipitates the blue hydroxid: 

CuS0 4 + 2KHO = Cu(HO) 2 + K 2 S0 4 . 

When heated, the turbid blue fluid turns black, as the hydroxid 
changes to cupric oxid: 

Cu(HO) 2 = H 2 + CuO. 

But if glucose be present, oxygen is taken out and red cuprous, 
oxid formed (Plate 8, Fig. 3), in accordance with this equation: 

2Cu(HO) 2 = 2 H 2 + O + Cu 2 0. 

Cuprous chlorid, CuCl, is formed when hydrochloric acid is. 
treated with excess of copper and the result added to water. It 
absorbs oxygen, changing to cupric chlorid and also carbon mon- 
oxid, forming Cu 2 Cl 2 CO . 2H 2 0. 

Cupric chlorid, CuCl 2 , is formed when cupric hydroxid is dis- 
solved in hydrochloric acid: Cu(HO) 2 + 2HC1= CuCl 2 + 2H 2 0. 

In concentrated solutions it is only slightly dissociated and,, 
therefore, has the greenish-yellow color of the CuQ 2 molecule;. 



COPPER 



303 



but when the solution is diluted, and thereby the dissociation 
increased, the blue color of the Cu** ions appears. By heating this 
blue solution or by adding excess of chlorin the dissociation is 
driven back and the blue turns green and finally yellow. 

Copper sulphate, CuS0 4 5H 2 0, commonly known under the 
trivial name of Milestone, occurs in large, blue, slightly efflorescent 
crystals, freely soluble in water, and having a strong metallic taste. 
The blue color is explained by the dissociation of the blue cupric 
ion in the water of crystallization. When heated the water is 
driven off and the anhydrous salt is white. It is used in medicine 
as an external application for its astringent or mild stimulating 
qualities. Internally, in doses of J to 2 gr., it is given as a tonic 
and astringent; in doses of 5 to 10 gr. it acts as a prompt emetic. 
It is employed in phosphorus-poisoning as an antidote and also 
as an emetic. In very large doses it is poisonous, and has been 
used both for suicidal and for homicidal purposes. 

Copper subacetate, Cu2'C 2 H 3 2 , CuO, is prepared by treating 
metallic copper with acetic acid in the air. It crystallizes in blue- 
green prisms. In an impure form it is known as verdigris. The 
same name is popularly given to other green salts of copper, as 
the oleate and carbonate. Verdigris in medicine is used only 
externally. In the arts it is frequently employed. 

Toxicology. — The irritant salts are copper sulphate (blue 
vitriol), copper subacetate (verdigris), and copper aceto-arsenite 
(Paris green). As the poisonous properties of the last named 
are dependent chiefly upon the arsenic, it has been considered 
among the compounds of that metal (p. 290). 

Metallic copper is not poisonous, as is demonstrated by the use 
of copper wire for surgical sutures and the absence of injurious 
consequences when a copper coin is swallowed. When used for 
sutures copper wire is found to exert a powerful inhibitory action 
on bacteria; in fact, much greater than that of any other metal. 

Symptoms of Acute Poisoning. — Out of 8 cases registered in 
England in ten years, 3 were suicidal, 5 were accidental, and none 
was homicidal. The very disagreeable taste of copper salts pre- 
vents the criminal use. The onset of the symptoms may be said 
to begin with this coppery astringent taste and the feeling of tight- 
ness in the throat. In a few minutes nausea and violent vomiting 
of greenish matters begin. Soon appear thirst, pain in the stomach, 
and colic, with violent purging of stools having the same green 
hue of the vomit. Ammonia-water added to the green excreta 
will turn them blue, and thus distinguish this copper-green from 
bile. The urine is scanty and may become albuminous, inky from 
changed hemoglobin, and loaded with tube-casts. The later 
stages are characterized by nervous phenomena, such as pains, 



304 THE METALS 

spasms which may be tetanic, paralysis, delirium, and collapse. 
In the course of a few days jaundice appears as a result of involve- 
ment of the liver. 

Fatal Dose. — Owing to the energetic emetic properties of large 
doses of copper sulphate, evacuation of the stomach is so prompt 
that we have no means of determining how much would prove 
fatal. On the one hand, a child four and a half years old has 
recovered after a dose of over \ oz. of copper sulphate; on the other 
hand, an adult has succumbed to a dose of \ oz. of verdigris. 

Fatal Period. — As a rule, life is prolonged for several days, the 
patient sometimes almost recovering from the symptoms of gastro- 
enteric irritation and finally dying from the effects of the absorbed 
poison. Copper sulphate has caused death in four hours. 

Treatment. — Evacuation of the stomach must first be obtained 
by stimulating the natural effort at vomiting. The antidote is the 
albumin of egg or the casein of milk. Eggs beaten in warm water 
should be given freely. If vomiting does not occur or is not 
active, the stomach-pump should be resorted to and the stomach 
washed out with milk or eggs and water. A milk diet with castor 
oil will favor removal from the intestine. 

Postmortem Appearances. — Congestion, swelling, softening, 
and excoriations of the mucous membrane of the stomach and 
bowels are usually found. The colon sometimes shows large 
ulcerations. A bluish discoloration of the lining membrane 
indicates that all the copper has not been evacuated. The liver 
may be soft and fatty, the kidneys swollen, and the tubules closed 
with bloody casts. 

Chronic Poisoning. — Until comparatively recent times it was 
thought that the slow introduction of minute doses of copper 
was 'injurious to the tissues by causing such pathologic changes 
as are known to be due to certain other poisons, such as phos- 
phorus, arsenic, antimony, lead, and mercury. It has been proved 
that as a slow poison copper belongs to a different category — 
that of silver and zinc. To produce toxic phenomena it must be 
given freely and intentionally. After a long course there are 
functional disturbances of the muscular and nervous systems, 
anemia, and cachexia. As soon as the administration ceases the 
functions are restored and the subject spontaneously recovers 
from the cachexia. It has not been demonstrated that any doses, 
however large, which have been taken with food have ever caused 
death, while medium doses in the beginning act as simple emetics, 
tolerance is rapidly established, and administration can be con- 
tinued for six months without danger. 

Copper salts are extensively used to impart a lively green 
color to pickled cucumbers and canned peas and beans. A 



COPPER 305 

permanent green compound is formed between copper and an 
acid derivative of the chlorophyl in the vegetable. Elaborate 
researches have been carried out in various countries under the 
highest sanitary authorities to settle the limit of copper admissible 
as not injurious to health. The U. S. Board of Food Inspection 
believes (1908) that copper sulphate used for the greening of 
vegetables is injurious and should be prohibited, but for the present 
admits to entry into the United States those vegetables which do 
not contain an excessive amount. The limit of excess was fixed 
in New York as any amount beyond 3 gr. of copper sulphate in 
1 lb. avoirdupois. 

At one time it was generally believed that workers in copper or 
its compounds, such as malachite, were liable to a disease called 
" copper colic," which differed from lead colic in that diarrhea 
was present instead of constipation; there was greater prostration, 
its duration was shorter, and the prognosis was good. It is now 
maintained by able investigators that such symptoms are not due 
to copper, but to the lead and arsenic which are impurities in most 
ores and in the commercial metal, or to the lead in the solder used 
by the operator. This is borne out by the fact that after more 
than one attack "drop-wrist" or lead-palsy is apt to supervene. 
No symptoms of poisoning are found in certain copper-workers 
who show copper as a purplish or bluish line on the gums, whose 
hair turns green, and whose urine stains the ground green. "The 
contention that there is no chronic copper poisoning in men or 
animals is at present uncontradicted." 

Tests. — Hydrogen Sulphid Test. — A stream of hydrogen sul- 
phid passed through an acid solution of a copper salt yields a 
brownish precipitate of copper sulphid, freely soluble in warm 
nitric acid, slightly so in excess of ammonium sulphid, but insoluble 
in the caustic alkalis. 

Ammonia Test. — A solution of a copper salt is either green or 
blue. By adding ammonium hydroxid in excess to a slightly 
colored solution, cupric hydroxid is formed and dissolved to 
make a much deeper sapphire-blue solution. 

Fallacies. — The salts of nickel give the same deep blue solu- 
tion. 

Delicacy. — The change in color is recognizable in 1 gr. of a 
solution containing yoVo g r - °f copper oxid. 

Potassium Ferrocyanid Test. — This reagent precipitates from 
a strong copper solution the reddish-brown copper ferrocyanid. 
When the solution is very dilute no precipitate falls, but the 
solution turns reddish brown. The brown precipitate is insoluble 
in acetic and hydrochloric acids, but with ammonium hydroxid 
forms a greenish-blue liquid. 



306 THE METALS 

Fallacies. — Solutions of uranium salts yield a similar brown 
precipitate, but when this is treated with excess of ammonium 
hydroxid the liquid is yellow, not blue. 

Interferences. — A trace of iron will give a blue color with this 
reagent and thus mask the result. 

Delicacy. — A distinct red reaction can be obtained from 2T9T9" 
gr. of copper oxid. 

Iron Test. — This test separates copper in the metallic state. It 
is performed by immersing a steel needle or other piece of bright 
steel or iron in the suspected liquid slightly acidulated. If copper 
be in solution, it will be deposited as a reddish layer on the iron. 
The solution tension of iron is much higher than that of copper; 
hence, the ions of copper give place to the iron and are precip- 
itated as metallic molecules. To prove that this film is copper 
it is dipped in ammonium hydroxid and exposed to the air, when 
the film of copper turns blue. 

Galvanic Zinc Test. — Very delicate results can be obtained by 
immersing in a copper solution a galvanic couple made by wrap- 
ping platinum wire around a piece of zinc-foil. The platinum is 
soon discolored by a deposit, the nature of which can be estab- 
lished by exposing it to the vapors arising from potassium bromid 
when treated with sulphuric acid. The deposit changes in color, 
and if rubbed on white porcelain leaves a violet mark. 

Electrolytic Test, — Having obtained the copper in solution and 
concentrated it, make it acid with hydrochloric acid and put it in 
a weighed dish of platinum which is connected with the zinc pole 
or cathode of a battery. A strip of platinum-foil as anode is 
immersed in the tested solution for twenty-four hours. In that 
time all the copper will be deposited on the platinum dish. To 
make a quantitative estimate the dish must be washed, dried, and 
weighed again. The gain represents the total amount of copper 
in the volume of tested solution. 

Separation of Copper from Animal Matters. — The organic 
matter in the contents of the stomach, or in the liver, brain, 
or other tissues, must be destroyed by burning to an ash and 
extracting with nitric acid, or boiling with hydrochloric acid 
and potassium chlorate, according to the systematic procedure 
given on p. 283. By evaporation the excess of acid can be re- 
moved, and the residue, dissolved in acidulated water, may be 
tested by the methods given above. 

MERCURY (Hydrargyrum) 

Symbol, Hg. Atomic weight, 200. 

Occurrence. — Quicksilver is found native, but the chief source 
is the sulphid ore, cinnabar, HgS. By simple heat the sulphur 



MERCURY 307 

oxidizes to S0 2 and the volatile metal vaporizes, to be collected 
as a distillate. 

Amalgams. — Mercury is a solvent for gold, silver, zinc, metals 
of the alkalis, and the alkaline earths and many other metals. 
This mercurial solution is called an amalgam of the metal dissolved. 

Physical Properties. — Mercury is the only metal that is in the 
liquid state at ordinary temperatures. It freezes at — 39.4 C. 
( — 40° F.), and boils at 357 ° C. (675 ° F.), but at all ordinary 
temperatures it vaporizes spontaneously. Having this great 
range of fluidity joined to the high density of 13.595, and not 
wetting glass, it is invaluable in the construction of barometers, 
thermometers, manometers, and other scientific instruments. 

Chemical Properties. — Mercury retains its silver-white, 
metallic luster in the air, because it combines with oxygen only 
at high temperatures. It unites directly with chlorin and the 
other halogens at ordinary temperatures. 

The Ions of Mercury. — Mercury forms two series of salts, 
mercurons and mercuric, in which the anions of acids are com- 
bined with two different elementary ions of mercury. In one 
series the mercurous ion (monomercurion), Hg*, is univalent; 
in the other the mercuric ion (dimercurion) , Hg**, is bivalent. 
With an excess of metallic mercury the product of the action of an 
acid such as nitric is mercurous. Without that excess the mer- 
curous nitrate passes to the condition of mercuric. Both ions are 
poisonous to bacteria and animal life. In the body the mercurous 
ion forms with chloridion a mercurous salt of low solubility and, 
therefore, of feeble powers, but the mercuric ion forms salts of 
higher solubility and of greater toxic activity. 

The metal is cleansed from impurities that impair its luster and 
make it "drag a tail" by shaking with dilute sulphuric acid to 
which a few drops of solution of potassium bichromate are added 
from time to time. The contaminating metals are oxidized and 
dissolved and can be washed away. 

When metallic mercury is finely triturated the globules re- 
main separate if the trituration has been done in the presence of 
some substance which gives a coating, such as fatty matter or a 
confection. 

The metal has been given in the pure state to remove obstruc- 
tion from the bowels mechanically, with no injurious consequences 
unless retained for a number of days. The metal is present, 
finely divided, and possibly oxidized in "gray powder" (hydrar- 
gyrum cum creta), "blue mass" (massa hydrargyri), "blue oint- 
ment" (unguentum hydrargyri). In this condition, and also if 
inhaled in the state of vapor, the metal is converted by the fluids 
of the body into active compounds which exhibit all its poisonous 



308 THE METALS 

effects. Among its poisonous salts are its oxids, iodids, mercur- 
ammonium chlorid, mercuric nitrate, and mercuric chlorid (cor- 
rosive sublimate). 

Mercurous Oxid (Hg 2 0) {Black Oxid).— This black insol- 
uble powder is precipitated from solutions of mercurous salts by 
bases: 

2 HgCl + 2NaOH = 2 NaCl + Hg 2 + H 2 0. 

It is unstable, changing in time to mercuric oxid and metallic 
mercury. Sunlight hastens this conversion: 

Hg 2 = HgO + Hg. 

Lotto hydrargyri nigra, or " black wash," is a mixture in which 
calomel is converted to mercurous oxid by lime-water, leaving 
calcium chlorid in solution: 

2 HgCl + Ca(OH) 2 = CaCl 2 + Hg 2 + H 2 0. 

Mercuric oxid, HgO, is obtained as a yellow powder by 
precipitation from mercuric salts with soluble bases. 

Hydrargyri oxidum flavum (yellow precipitate) is formed when 
a solution of mercuric chlorid is poured into a solution of sodium 
hydroxid: 

HgCl 2 + 2 NaHO = 2NaCl + HgO + H 2 0. 

It is slightly soluble in water, imparting an alkaline reaction 
and metallic taste. 

The color of mercuric oxid depends upon the fineness of division. 
When precipitated from cold solutions it is yellow; from hot 
solutions it is orange. In both cases it is finely divided and in 
consequence energetic. 

As the "red precipitate" it is more compact, coarser, and 
crystalline; its official name then being hydrargyri oxidum rubrum. 
It is obtained by heating either mercurous or mercuric nitrate 
moderately, oxygen and nitrogen peroxid being driven off and 
the red oxid left behind: 

Hg(N0 3 ) 2 = HgO + 2N0 2 + O. 

Mercuric oxid is partly dissolved and partly suspended in 
"yellow wash," lotio hydrargyri flava, which is obtained when a 
solution of corrosive sublimate is poured into lime-water: 

HgCl 2 + Ca(OH) 2 = CaCl 2 + HgO + H 2 0. 



MERCURY 309 

Oleatum hydrargyri contains 25 per cent, by weight of the 
yellow oxid. 

There is a 10-per cent, ointment of "yellow precipitate," 
unguentum hydrargyri oxidi flavi, and one of "red precipitate" 
of the same strength, unguentum hydrargyri oxidi rubri. 

Mercurous chlorid, HgCl (hydrargyrum chloridum mite, mild 
chlorid, calomel), can be made by subliming a mixture of mer- 
curic chlorid and metallic mercury: 

HgCl 2 + Hg aHgCl. 

Precipitated calomel is a more active form, owing to the fineness 
of its division. A solution of mercurous nitrate yields mercurous 
chlorid when acted upon by sodium chlorid: 

HgN0 3 + NaCl = HgCl + NaN0 3 . 

Calomel is a heavy, white, insoluble, tasteless powder that is 
not considered poisonous. If retained too long it changes to 
some more active compound, such as the poisonous mercuric 
chlorid, and then produces systemic symptoms. It is so exten- 
sively used that milder toxic effects are not infrequent, owing to 
these changes in the stomach or in the prescription, due to incom- 
patible association. It is probable that most of the few fatal cases 
reported were brought about by the conversion of the calomel 
by the fluids of the body into some poisonous salt. It is readily 
oxidized to the mercuric chlorid. It is converted into mercuric 
chlorid by nitrohydrochloric acid and chlorin-water, and probably 
to a slight extent also by hydrochloric acid and alkaline chlorids. 
It is changed to oxid or reduced by the alkaline bases and carbo- 
nates. Prolonged exposure to sunlight changes it to metallic 
mercury and mercuric chlorid, as is shown by this equation: 

2 HgCl Hg + HgCl 2 . 

The HgCl is of such difficult solubility that few Hg ions are 
dissociated from it in a brief sojourn in the body, but the HgCl 2 is 
freely soluble, dissociates Hg ions promptly, and, therefore, is 
more active in every way. Calomel should be kept in opaque 
containers in order to prevent this change. 

It is incompatible with halogens, chlorids, bromids, iodids, 
sulphates, carbonates, hydrates, acids, alkalis, soap, cocain, hydro- 
cyanic acid and cyanids, sulphurous acid, hydrogen peroxid, iodo- 
form, salts of lead, copper, or silver; sugar, tragacanth, acacia,, 
pilocarpin, antipyrin, acetanilid, and sweet spirits of niter. 



310 THE METALS 

Dose as cathartic: 5 to 15 gr. (0.33-1.0 gm.); as internal anti- 
septic, J to J gr. every hour. 

Mercuric Chlorid (HgCl 2 ) (Hydrargyri Chloridum Corro- 
sivum, Corrosive Chlorid, Bichlorid oj Mercury). — This salt is com- 
monly called corrosive sublimate, because it is a local corrosive 
and is prepared by subliming a mixture of mercuric sulphate and 
sodium chlorid: 

HgS0 4 + 2 NaCl = Na 2 S0 4 + HgCl 2 . 

Corrosive sublimate is usually seen in crystalline masses; it 
sublimes at 82. 2 C. (180 F.), and is deposited in needles, in 
octahedra, or in stellate aggregations of crystalline plates (Fig. 69). 




Fig. 69. — Sublimate of mercuric chlorid, magnified. Stellate crystals. 

It has no odor, but an acrid, metallic taste. It is soluble in 16 
parts of cold water and 3 parts of boiling water, but is far more 
soluble in solutions of common salt or other alkaline chlorids, 
forming salts of the anions (HgCl 3 )' and (HgCl 4 )", such as Na(HgCl 3 ) 
and Na 2 (HgCl 4 ), which have less bactericidal power than the 
simple mercuric chlorid in a concentration containing the same 
amount of mercury. Mercuric chlorid alone is dissociated very 
little, as compared with sodium chlorid alone. The double chlorid 
is dissociated even less. The germicidal power of mercury salts 
is proportionate to the simple mercuric ion and not to the other 



MERCURY 



311 



component. Hence, the addition of NaCl to a concentrated 
solution of HgCl 2 locking up some of the Hg in the complex 
(HgCl 3 )' lessens the number of active Hg" ions and lowers the 
germicidal power. To make antiseptic solution it is best to use 
pastilles containing not more than 4 parts of NaCl to 1 of HgCl 2 
and dissolving only 1 gram per liter. At this dilution the NaCl 
favors the solution of the HgCl 2 without material reduction of 
germicidal action. In the presence of the organic exudations of 
a wound, changes occur which cause the dissociation of more 
mercuric ions to take the place of those taken up by the protein. 
Mercuric chlorid makes a definite insoluble compound with proteid 
matter, and is, therefore, fatal to low forms of animal and vegetable 
life. In the dry powder it is inactive chemically and also as a 
bactericide. Dissolved in alcohol or ether it has little antiseptic 
power because in these solvents it dissociates very few Hg" ions. 
In water it supplies the poisonous mercuric ion and exhibits its 
reactions very well. A solution of it is used in the household 
to destroy bedbugs, and by taxidermists to preserve skins and 
mounted preparations. In antiseptic surgery it is extensively 
employed in irrigating solutions of 1 : 4000 or even 1 : 1000 of water. 
As it attacks metals it is not suited for disinfecting metallic vessels 
or instruments. 

It is incompatible with sulphurous acid and other reducing 
agents (which reduce it to calomel), ferrum redactum, arsenous, 
antimonious, and ferrous salts; formic acid; albumin, gelatin, 
alkalis; alkaloids; soap; lime-water; bromids; iodids; borax; 
carbonates, phosphates, hypophosphites, salts of copper, zinc, 
lead, and silver; syr. sarsaparilla comp.; tannic acid and vegetable 
astringents. Dose: -ro to ^ g r - (0.00075-0.006 gm.). 

Mercurous Iodid (Hgl) {Hydrargyri Iodidum Flavum, Green 
Iodid, Yellow Iodid, Protiodid). — An acid solution of mercurous 
nitrate treated with potassium iodid gives a yellow precipitate of 
mercurous iodid: 

HgN0 3 + KI KNO3 + Hgl. 

It is a tasteless, almost insoluble, powder which decomposes by 
sunlight into mercuric iodid and mercury, becoming greenish from 
the presence of the blue particles of metallic mercury. Thus: 
2HgI = Hg + HgI 2 . Mercurous iodid should not be prescribed 
with soluble iodids or the more energetic mercuric iodid will be 
formed. Dose: \ to 1 gr. (o. 01 1-0.066 gm.). 

Mercuric Iodid (Hgl 2 ) {Hydrargyri Iodidum Rnbrum, Red 
Iodid, Biniodid). — When a solution of potassium iodid is added to 
one of mercuric chlorid a yellow precipitate falls, which at once 



312 THE METALS 

turns red on the side to the light and eventually gets red through- 
out. This red iodid dissolves on the addition of an excess of 
potassium iodid: 

HgCl 2 + 2KI = 2KCI + Hgl 2 . 

A brilliant-red, tasteless powder, it is very sparingly soluble in 
water. When it dissolves in the iodid of potassium, a salt is 
formed, called potassium mercuric iodid, by this reaction: 

2KI + Hgl 2 = K 2 HgI 4 . 

This salt does not show the usual chemical reactions of mercury, 
and is less apt to salivate than simple HgCl 2 in doses containing 
the same amount of Hg. Obviously it dissociates very few simple 
mercuric ions and is properly regarded as a salt, the anion of which 
is (Hgl 4 )". Nessler's reagent is prepared by adding potassium 
hydroxid to this potassium mercuric iodid. It is a sensitive test 
for ammonia. Dose of mercuric iodid: yo to yq g r - (0.0013— 
0.006 gm.). 

Its incompatibles are the same as those of mercuric chlorid 
given above. 

Mercuric Sulphid (HgS) {Vermillion).— There is no mer- 
curous sulphid, but the mercuric compound is very stable. It is 
found in the ore cinnabar, and can be formed by direct union of 
the elements. The black precipitate formed on passing hydrogen 
sulphid through a mercurous solution is not mercurous sulphid, 
unless as a transient phase. Its final composition is a mixture of 
mercuric sulphid and mercury: 

2HgCl + H 2 S = HgS + Hg + 2HCL 

If the hydrogen sulphid be passed through a mercuric solu- 
tion, whether acid or neutral, the precipitate is at first white, then 
yellow, red, and black. These are more or less complex and 
variable compounds of mercuric sulphid with other mercury salts 
present. Eventually the mass of sulphid overcomes the other 
salts and a pure black precipitate of mercuric sulphid remains. 
This black amorphous sulphid is a less stable modification, which 
can be made to change by sublimation to the permanent red crys- 
talline form known as vermillion. 

Mercurous sulphate, Hg 2 S0 4 , is prepared by warming mer- 
cury with strong sulphuric acid. There is evolution of sulphur 
dioxid, and the sulphate is deposited as a white powder of difficult 
solubility. This powder is the starting-point in the manufacture 



MERCURY 313 

of other mercury salts. It is also used in making standard electric 
cells. 

Mercuric sulphate, HgS0 4 , is formed when the mercurous 
salt is heated with excess of sulphuric acid. There is evolution 
of sulphur dioxid, and the heavy, white, crystalline mercuric sul- 
phate is precipitated. On treating this normal salt with boiling 
water the yellow basic salt is formed, and an acid salt remains in 
solution. The basic salt has been used in medicine under the 
name of Hydrargyri subsulphas flavus or (oxysulphate or turpeth 
mineral). Its formula is Hg 3 S0 4 (OH) 4 , and it is sometimes 
regarded as a compound of the sulphate and oxid. It is a yellow, 
tasteless, insoluble powder. Dose as an emetic: 3 to 5 gr. (0.2- 
o-33 g m 0- 

Mercurous Nitrate, HgN0 3 , and Mercuric Nitrate, 

Hg(N0 3 ) 2 . — When mercury is dissolved in cold nitric acid with 
excess of the metal, the mercurous salt is formed; if the acid be 
in excess and be heated, then the mercuric nitrate is the product. 
The white salts thus obtained dissolve in water containing free 
acid; but, without the acid, water changes them to an insoluble 
basic nitrate, with the composition Hg 3 (N0 3 ) 2 (OH) 4 , analogous to 
the basic sulphate. To prove that the mercuric salt is the product, 
dilute and add hydrochloric acid. If any mercurous nitrate 
be present, the white mercurous chlorid will be precipitated and 
more hot nitric acid is needed. 

Liquor hydrargyri nitratis is a liquid containing mercuric nitrate 
60 per cent, and free nitric acid 11 per cent. It is a colorless, 
heavy liquid with a strongly acid reaction, used as an escharotic. 
Unguentum hydrargyri nitratis is its ointment, having a bright 
citrine color. 

Ammoniated Mercury (NH 2 HgCl) (Hydrargyrum Ammonia- 
tum, White Precipitate). — If mercuric chlorid be added to cold 
ammonium hydroxid in excess, a white precipitate of ( mercuric 
ammonium chlorid forms. 

HgCl 2 + 2 NH 4 OH = NH 2 HgCl + NH 4 Cl + 2H 2 0. 

This tasteless and insoluble powder is dissipated by heat with- 
out melting. It is ammonium chlorid, NH 4 C1, in which two 
hydrogen atoms have been replaced by mercury. A 10-per cent, 
ointment is official under the name of unguentum hydrargyri 
ammoniati. 

When a mercurous salt is added to ammonium hydroxid a 
black precipitate falls which may contain metallic mercury with 
the salt described above. It is probably a complex mixture in 
which there exists some mercurous chloramid, NH 2 Hg 2 Cl. By 



314 THE METALS 

the same reaction paper wet with mercurous nitrate is blackened 
by the vapor of ammonia. 

Toxicology of Salts of Mercury.— Symptoms.— Corrosive 

sublimate is the salt to which mercury poisoning can be most 
frequently attributed. However administered, it is a very active 
gastro-intestinal irritant. When taken by the mouth, the symp- 
toms usually begin within a few minutes. The onset is never 
delayed half an hour. There are an acrid, metallic taste, con- 
striction of the throat, retching, and a burning sensation in the 
gullet and stomach. A white coating forms at once on the shriv- 
eled lining of the mouth, the inflammation of the throat may 
involve the larynx, and acute swelling of the glottis may cause 
asphyxia. The pain in the stomach is so severe as to cause faint- 
ing. It comes on promptly, attended by nausea and vomiting 
of material streaked with blood, and later on purging and strain- 
ing with bloody stools. Free hemorrhages occur from the stomach, 
bowels, or other outlet. The urine is scanty or suppressed, 
the temperature may be febrile or subnormal, the respiration 
difficult, the pulse thready and irregular. Death is preceded by 
collapse, unconsciousness, or convulsions. 

Fatal results have followed the application of an alcoholic 
solution of corrosive sublimate (80 gr. to 1 oz.) to the scalp for 
ringworm. Two cases resulted fatally, from poisoning, by the 
external application of an ointment of corrosive sublimate to 
cure the itch. In these cases, besides the painful local inflam- 
mation, in a few days gastro-intestinal symptoms appeared, such 
as vomiting and purging with tenesmus. In addition, there were 
stomatitis, fetid breath, fever, scanty urine, and collapse. When 
the poison is absorbed as a result of irrigation of wounds of the 
vagina, uterus, or abscess cavities, the digestive organs also are 
profoundly affected. An early effect is serous diarrhea, which 
afterward becomes bloody, attended by colic and tenesmus, nausea, 
and vomiting. The urine is usually albuminous, containing 
epithelial cells and granular casts. While there may be severe 
headache, insomnia, dimness of vision, and transient disturbance 
of the intellect, the mind is usually clear to the end. The pulse 
grows weaker, the pupils contract, the temperature falls, and 
sometimes an intense erythema appears. The great frequency 
of deaths from antiseptic irrigations with corrosive sublimate 
pleads for its disuse in obstetric practice. 

Fatal Dose. — It is probable that fatal consequences would 
follow doses of 3 to 5 gr. of corrosive sublimate. Recovery has 
resulted after the administration of 100 gr. under prompt treat- 
ment by milk, eggs, and emetics. White precipitate or mercur- 
ammonium chlorid was at one time regarded as non-poisonous. 



MERCURY 



315 



Several deaths from it have been reported — one from 35 gr. Red 
precipitate has caused acute gastro-intestinal irritation when given 
in doses of 2 dr. or more. Acid mercuric nitrate, intended to 
be used externally only as an escharotic, has been followed by 
death after such use, and also when administered internally. The 
yellow subsulphate, or turpeth mineral, used in the treatment of 
croup, has often caused alarming symptoms. Two doses of 3 gr. 
each have been sufficient to cause death. 

Fatal Period. — Death may occur in half an hour, but com- 
monly life is prolonged for from two to four days, and it may last 
into the second week. 

Treatment. — Vomiting should be encouraged by large drafts 
of milk containing emetics. The casein, like all albuminous com- 
pounds, acts as an antidote. The most convenient albumin should 
be given freely. This may be raw eggs, flour paste for its gluten, 
or blood from a freshly killed fowl, given in milk or water. Mag- 
nesia would prove beneficial by conversion of the corrosive sub- 
limate to a less injurious compound. It should not be forgotten 
that the albuminate of mercury may dissolve in excess of albumin; 
hence emetics are called for after the antidote has been given. 
The pain, purging, and tenesmus will require such treatment as 
is usually given for gastro-enteritis. 

Postmortem Appearances. — Some parts of the alimentary 
canal are sure to show inflammatory change. In the mouth, throat, 
and stomach there will be patches of congestion and erosion, or the 
intestines, especially the colon, may be the seat of inflammation. 
Eventually the kidneys swell and take on acute inflammation. 

Even when death has occurred from absorption of the poison 
as a result of application to the skin or irrigation of abscesses or 
of wounds, or of the uterus and vagina, the most important lesions 
are in the digestive tract, especially the colon. There is hyperemia 
of the mucous membrane, of the colon, with easy detachment of 
the epithelium, patches of superficial necrosis in some parts, and 
in others a diphtheritic coating infiltrating the deeper layers. The 
kidneys show a characteristic acute parenchymatous nephritis. 
In some cases the peritoneum is slightly injected. The liver 
shows no marked lesion, but is generally pale and anemic. The 
other organs may be unaffected. 

Chronic Poisoning or Mercurialism. — The operatives in 
quicksilver mines, mirror-makers, fire gilders, thermometer- and 
barometer-makers, furriers, and hatters are liable to a chronic 
disease ending in paralysis, brought about by the daily intro- 
duction and accumulation in the system of minute doses of mer- 
cury. Some of the milder symptoms have been induced by the 
incautious use of mercurials in the treatment of secondary syphilis, 



316 THE METALS 

and by repeated applications to the skin of a weak lotion of cor- 
rosive sublimate for cosmetic purposes. 

The symptoms shown in chronic mercurial poisoning are often 
quite complex. Ptyalism, or salivation, is usually present; the 
secretion of saliva is profuse, and is attended with swelling and 
tenderness in the salivary glands; the gums become red, spongy, 
and tender, with occasionally a blue line near the teeth; the tongue 
is swollen and painful; ulcers form in the mouth, and the breath 
is very fetid. The teeth are loosened, and the alveolar processes 
sometimes become the seat* of acute periostitis. There is usually 
loss of appetite, with attacks of nausea and vomiting. In some 
cases colic and diarrhea are present. Soon supervene depressed 
energies, loss of weight, anemia, and a peculiar cachexia with 
eruptions of erythema or eczema. The nervous system is even- 
tually involved, showing attacks of cerebral excitability and 
insomnia, or perhaps hebetude of mind. In the end a peculiar 
fine tremor spreads from the tongue and face to the upper and 
lower extremities. The tendency of these tremblings is to progress 
from the jerky and intermittent form, brought on by excitement 
or exertion, to the continuous, which lessens only during sleep. 
The muscles grow weaker, without loss of electrocontractility. 

Disturbances of sensation are common; sometimes neuralgia, 
is a symptom, at times appearing as numbness and tingling in 
anesthetic patches. Affections of sight and hearing are not. 
infrequent. 

The postmortem appearances indicate that mercury, like arsenic, 
and lead, has the power to excite a progressive peripheral neuritis. 
The localized mercurial palsies differ from the lead palsies in that 
the electrocontractility is unimpaired, there is no atrophy, and. 
the tendon reflexes persist. The characteristic nerve lesion is a 
destruction of the myelin, with preservation of the axis cylinder. 
The trophic changes are pigmentary and peri-axile. 

Treatment of Chronic Mercurialism. — Improvement usually 
follows removal of the patient from the surroundings where he was 
exposed to the poison. Although elimination of a single dose is 
usually complete in a few days by means of the salivary glands, 
the kidneys, the intestines, and in less degree by the sweat and 
milk, still if the period of absorption has been prolonged, as it is 
in chronic mercurialism, some portion of the poison may be 
retained, combined with albuminous bodies in an inactive state 
for many months. To stimulate the process of elimination and 
to secure the oxidation of the albuminous compound so as to set 
free the mercury, the bowels should be kept opened, the action 
of the skin promoted by warm baths, and the best hygienic and 
tonic regimen instituted. It is customary to administer potas- 



MERCURY 



317 



sium iodid in small doses in the belief that it changes the deposited 
poison into mercuric iodid, which is soluble in excess of the potas- 
sium salt, and is by this means conveyed into the excretory fluids. 
For the paralysis, massage and electricity are indicated; for the 
salivation, mild mouth-washes of potassium chlorate or borax 
are called for. 

Tests. — Sublimation Test for Compounds in the Solid 
State. — The suspected solid is first thoroughly dried, mixed with 
dry sodium carbonate, and heated gently in a reduction tube. A 
shining ring forms on the inside of the tube in the cooler part. 
A lens resolves this sublimate into minute shining spheres of 
metallic mercury. The corresponding sublimate of arsenic and 




Fig. 70. — Sublimate of metallic mercury, magnified. 

antimony are not of this shape. Rubbed with a glass rod, these 
globules run together into larger rounded masses. A few scales 
of iodin left in the closed tube for a few hours will vaporize and 
convert the mercury into a film of yellow, and later of red, mercuric 
iodid. If this test be done in a small subliming cell, such as is 
described under Arsenic (p. 277), and collected on a slide for 
microscopic examination, it is of very great delicacy (Fig. 70). 

Hydrogen Sulphid Test. — A solution of a mercurial salt acidu- 
lated with hydrochloric acid yields a black precipitate when 
treated with a stream of hydrogen sulphid. The formation of 
the mercuric sulphid through intermediate stages is shown if the 



318 THE METALS 

tested solution is strong; the precipitate becomes successively 
yellowish white, dark yellow, orange, brown, and black. The 
precipitate is insoluble in caustic alkalis, alkaline sulphids, and 
nitric or hydrochloric acids. It can be identified by yielding the 
globular sublimate when dried and heated with sodium carbonate, 
as directed above. By drying the sulphid in an air oven and 
weighing, the quantity of mercury can be calculated. 

Reinsch's Test. — The procedure is the same as that given 
under Arsenic (p. 277). A strip of bright, pure copper-foil will 
receive a gray or silvery deposit in a few minutes from a boiling 
mercurial solution acidified with hydrochloric acid. Having 
carefully washed the coated copper in water and dried it, the 
slip should be heated in a small dry reduction tube, and the re- 
sulting sublimate examined for globules, as stated above, and 
tested with free iodin. 

Fallacies. — This test yields a metallic deposit on copper from 
arsenic, antimony, bismuth, silver, and some rarer metals. Coat- 
ings of arsenic, antimony, and mercury are the only ones that 
give a sublimate when heated in a reduction tube. 

Mercury is peculiar in its opaque globular form and the bright 
high lights under reflected light (Fig. 70). 

Delicacy. — Using capillary reduction tubes of peculiar con- 
struction, characteristic globules have been obtained from g 0*0 
gr. of corrosive sublimate; under ordinary manipulation twoo"o g r - 
is nearer to the limit of delicacy. 

Galvanic Gold Test. — A band of goldfoil is wrapped about a 
strip of thin zinc, leaving some zinc exposed, thus making a gal- 
vanic couple. Having acidulated the suspected liquid with hy- 
drochloric acid and warmed it, the two metals are hung in it for 
several hours. A silvery deposit on the gold indicates mercury. 
After washing the gold successively in water, alcohol, and ether, 
it may be heated in a reduction tube and the sublimate of mer- 
curial globules produced may be identified, as stated under sub- 
limation test. 

Potassium Iodid Test. — On adding potassium iodid to a solu- 
tion of corrosive sublimate or other mercuric salt a precipitate 
falls, at first yellow, but rapidly changing to red mercuric iodid. 
This will dissolve in excess of the potassium iodid. 

Distribution in the Tissues.— Riederen gave to a dog in 
thirty-one days 2.789 gm. of calomel (2.368 gm. Hg.). By anal- 
ysis he recovered 2.2 gm. of mercuric sulphid {1.9 gm. Hg.), of 
which there were in the feces 95 per cent., or 2.1 175 gm.; in the 
urine, 0.055; m the brain, heart, lungs, spleen, pancreas, kidneys, 
scrotum, and penis, 0.009; m the liver, 0.014; i n the muscles, 
0.0114. If the poison find access to the body by external appli- 



MERCURY 319 

cation or by irrigation of other cavities than the alimentary tract, 
it should be looked for in the liver, the urine, and the kidneys. 
Other cases have been reported which established the fact that 
in a few days the whole amount of one poisonous dose given by 
the mouth may escape from the body. 

There is liability to error if the analyst loses sight of the well- 
known fact that traces of mercury are very commonly found in 
the stomach, bowels, liver, kidneys, and other organs of the cadaver 
with no history of recent dosage from the poison. These are 
probably accumulations from small non-poisonous doses of 
blue mass or calomel, or perhaps vestiges of a previous mercurial 
treatment of syphilis. 

Detection. — A ready, casual examination can be made of 
the vomited matters or urine by decanting the liquid portion, 
evaporating it to dryness, treating with pure hydrochloric acid, 
and applying Reinsch's test, the galvanic gold test, or the elec- 
trolytic test. 

Separation from the tissues or other organic matter is 
accomplished by the systematic method referred to under Arsenic. 
To disintegrate the organic matter thoroughly it must be finely 
minced and heated on a water-bath for some time with equal 
parts of water and hydrochloric acid, while potassium chlorate 
is added in small amounts until a clear solution is made. After 
filtration the solution is heated gently to expel the chlorin and a 
stream of hydrogen sulphid is passed until the metal is all pre- 
cipitated as sulphid. A portion of this sulphid may be tested by 
reduction and sublimation, or it may be dissolved by gentle heat 
in nitrohydrochloric acid, the solution evaporated to dryness on 
a water-bath, redissolved in warm water, and the above tests be 
applied or the mercury separated by electrolysis. 

Electrolysis may be performed conveniently by the method of 
Mann. The suspected solution is put in a glass cell having a 
bottom of parchment-paper, and immersed to a common level in 
an outer vessel of water acidulated with sulphuric acid. The 
cathode of a battery of four Grove cells, made of a slip of gold- 
foil, is fixed into the inner vessel near to and parallel with the 
bottom. In the outer liquid is set the anode, a strip of platinum 
opposite to the cathode. After the current has passed six hours, 
the gold coated with mercury is washed successively with water, 
alcohol, and ether, and weighed. By heating the gold-foil in a 
hard glass open tube of known weight the mercury sublimes and 
is deposited on the tube. 

Quantitative determination may be made by finding the loss 
of weight of the gold-foil carrying a film of mercury when heated 
as above described. This gives the weight of mercury in the 



320 THE METALS 

portion of fluid tested; it can be controlled by calculating the 
increase of weight in the tube. Instead of using electrolysis, the 
amount of corrosive chlorid present in any fluid in which mercury 
is sought may be determined simply by boiling the materials in 
water, straining, filtering, and agitation of the filtrate with ether, 
separation, and evaporation of the ethereal extract. The dried 
residue dissolved in water may be precipitated with volumetric 
solution of silver nitrate, the chlorin estimated, and from this the 
weight of mercuric chlorid calculated. 

Urine examination may be made by electrolysis, Reinsch's 
test, or by Mayer's method, which follows: Having evaporated the 
urine to dryness, the residue, mixed with quicklime and slaked 
lime, is heated in a combustion tube, condensing the mercury on 
the cooler part. 

Rapid Method. — Separate the mercury from organic combina- 
tions by heating to the boiling-point in a porcelain dish a mixture 
of 20 fl. oz. (600 c.c.) of urine with 4 fl. oz. (100 c.c.) of hydro- 
chloric acid and 7 gr. (0.50 gm.) of potassium chlorate. Before 
it has cooled it is poured through a filter (if turbid) into a funnel 
having a stopcock, previously adjusted to permit 100 c.c. to pass 
in one minute. The end of the funnel rests in a smaller funnel- 
tube, the outlet of which has been heated and drawn into a fine 
opening. Inside this narrowed tube has been placed a small 
spiral of bright copper-foil. Having passed all the urine through 
the funnels and over the copper, the operation is repeated six 
times, keeping the urine hot. If mercury be deposited, the cop- 
per will change color. The copper spiral is taken out with for- 
ceps, washed in water, alcohol, and ether, dried, and heated in a 
narrow tube. The mercury vaporizes and is condensed as glob- 
ules on the glass. 

LEAD (Plumbum) 

Symbol, Pb. Atomic weight, 207. 

There are numerous compounds of lead in nature, the most 
important being galena, the sulphid, PbS. This is roasted till 
oxidized and the oxid is reduced with carbon. 

Properties. — Lead is a soft bluish-white metal, heavy, but of 
low melting-point, 325 C. (617 F.). Freshly cut surfaces have 
a brilliant luster which is soon lost, a superficial layer of oxid being 
deposited by the action of the air. The softness, pliability, and 
low melting-point of lead make it a convenient material for 
plumber's pipe. Soft solder is an alloy of lead and tin. Type metal 
contains lead, tin, and antimony. Pewter contains lead and tin. 
Metallic lead dissolves freely in nitric acid, sparingly in strong 
sulphuric acid when hot, but not in dilute or cold sulphuric acid, 






LEAD 321 

nor practically in hydrochloric acid. The metal, when embedded 
in the tissues as a bullet, exerts no local specific action, being 
insoluble in the fluids there. While not soluble in pure water, 
the ordinary water served in plumber's pipes contains enough free 
oxygen to oxidize a fresh lead surface, which may then form a 
soluble bicarbonate by the aid of the carbon dioxid present. A 
portion of it finally forms a crust of insoluble hydrated oxycar- 
bonate, which prevents further action. While silicates, sulphates, 
and carbonates tend to prevent the corrosive action of water, 
it is increased by nitrites, nitrates, and chlorids. Hence, a hard 
water supply is less dangerous when served in lead pipes than a 
"soft*' or purer article. 

The Ions of Lead. — The element itself forms a bivalent cation, 
Pb**, called plumbion, and an unstable quadrivalent plumbion, 
Pb****. Plumbion is without color and is a potent poison. When 
lead is acted upon by air and water a white precipitate of lead 
hydroxid, Pb(OH) 2 , forms which behaves toward alkalis just as 
does alumina — that is, it dissolves in excess of alkali, but not 
in ammonia. With those bases it forms soluble plumbites, the 
hydroxid having split off hydrogen to form complex anions, such 
as (PbO,)" and (HPb0 2 ) / .' A hypothetic hydroxid, Pb(OH) 4 , is 
supposed to contain the quadrivalent anion (PbOJ"", and has 
received the name of normal plumbic acid. This, by the loss of 
water, forms meta plumbic acid, H 2 Pb0 3 . With calcium the 
former makes calcium plumbate, Ca 2 Pb0 4 ; with sodium the latter 
makes sodium meta plumbate, Na 2 Pb0 3 . These acids combine 
with lead itself to make Pb 2 Pb0 4 or Pb 3 4 , minium, and PbPb0 3 
or Pb 2 3 , the sesqnioxid. 

Lead Oxid (PbO) {Plumbi Oxidum, Litharge).— When air 
or oxygen is caused to pass over salts of lead, heated or melted 
lead, a yellow powder forms. This powder, fused at a higher 
temperature, forms yellowish crystalline scales of PbO called 
commercially litharge. Continued gentle heat in air changes it 
to a bright-red powder, Pb 3 4 , used as a pigment under the names 
red lead, or minium. If the red lead be oxidized by heating with 
nitric acid, a dark-brown powder forms, the dioxid or peroxid, 
Pb0 2 . The oxid, PbO, dissolves sparingly in water, imparting 
an alkaline reaction, due to the formation of lead hydroxid, Pb 
(OH) 2 . It is strongly basic, decomposing alkaline salts. With 
the fatty acids of oils it unites to form lead soaps, the most im- 
portant of which is lead oleate or emplastrum plumbi. Heated 
with milk of lime its hydroxid develops acid properties as H 2 Pb0 2 , 
forming a soluble crystalline calcium plumbite, CaPbO,, used as a 
hair dye. 

Lead dioxid (Pb0 2 ) (peroxid, brown oxid, puce oxid) is an 



322 THE METALS 

insoluble dark brown powder, readily yielding half its oxygen when 
heated. It is much used in the laboratory as an oxidizing reagent. 

Lead chlorid, PbCl 2 , is formed by a reaction between a sol- 
uble lead salt and a chlorid; or whenever plumbion and chloridion 
are brought together in concentrated solution. It is a white 
crystal, very sparingly soluble. Uniting with lead oxid it forms 
several basic or oxychlorids of a yellow color, which are used as 
pigments under the names of Turner's, Naples, Verona, or Paris 
yellow. 

Lead nitrate, Pb(N0 3 ) 2 , is prepared by dissolving lead or 
lead oxid in dilute nitric acid. While readily soluble in water it 
is very sparingly soluble in strong nitric acid. It is white and 
sweetish, the after-taste being metallic and astringent. 

Lead sulphate, PbS0 4 , is formed when hot strong sulphuric 
acid acts on lead. It is the heavy white precipitate that falls 
when plumbion, Pb", meets sulphanion, (S0 4 ) // , as happens when 
sodium or magnesium sulphate is given as an antidote to lead- 
poisoning, thus: 

Pb", (NO,)', (NO,)', + K-, K-, (S0 4 )" = 
K-, (NO,)' + K', (NO,)' + PbS0 4 . 

It is sometimes used to give weight or body to white silk, and 
from this fabric it may be taken accidentally by seamstresses. 

The storage battery or accumulator contains a plate of lead and 
one of lead dioxid, Pb0 2 , immersed in sulphuric acid. A charging 
electric current, having been sent through the cell, has accumulated 
as intrinsic or chemical energy in the Pb"", 2 ". When the 
circuit is closed this stored energy flows back as a discharging 
electric current while the two plates are both converted to lead 
sulphate. The quadrivalent Pb"" in the Pb0 2 gives up two 
charges of electricity to become the Pb" in PbS0 4 . The battery 
is restored by a charging current which reverses the reaction, 
raising the Pb" to its former state of Pb"". 

Lead Carbonate (2(PbCO,). Pb(OH) 2 ) {PlumU Carbonas, 
White Lead). — The paint known variously as white lead, flake 
white, and mineral white is a mixture of lead hydroxid and neu- 
tral lead carbonate. It is present in the official ointment of lead 
carbonate. It is the white precipitate formed when plumbion, 
Pb", and carbanion (CO,)", meet in the same solution. To 
facilitate the reaction between lead oxid and carbon dioxid the 
vapor of acetic acid is used as an intermediary. First a basic 
acetate is formed, and this changes to the basic carbonate. It is 
a smooth, white, insoluble, tasteless powder, invaluable as a base 
for paints. Sometimes it has been used as a cosmetic with the 



LEAD 



3 2 3 



most deplorable consequences. It is the most common cause of 
chronic lead-poisoning. 

Lead chromate, PbCr0 4 , is the heavy yellow precipitate formed 
when plumbion, Pb", meets chromanion (Cr0 4 ) // . 

Pb", (NO,)', (NO,)' + K-, K«, (CrOJ" = 
K', (N0 3 )' + K, (NO a )' + PbCr0 4 . 

It is an amorphous, insoluble powder used as a pigment under 
the name chrome yellow. The basic chromate is known as chrome 
orange. 

Lead acetate, Pb(C 2 H 3 2 ) 2 3H 2 0, plumbi acetas, is made by 
the action of acetic acid on lead oxid. It occurs in white masses 
of acicular crystals. It is soluble in water, and has a taste at 
first sweetish, hence the popular name, sugar oj lead, but later 
the taste is styptic and metallic in character. It is present in 
pharmaceutic preparations, as a pill, with opium, a compound 
suppository with opium, and an ointment. The subacetate, 
Pb(C 2 H 3 2 ) 2 PbO, made by dissolving the oxid in solutions of the 
acetate, is present (25 per cent.) in liquor plumbi subacetatis, " Goul- 
ard's Extract;" in a dilute form (1 per cent.) in liquor plumbi 
subacetatis dilutus (lead-water), and in the compound cerate or 
Goulard's cerate. Clear solutions soon turn white from the action 
of carbon dioxid in the air. This tendency is arrested by adding 
acetic acid in excess. This property is not shared by the solution 
of the nitrate, which keeps clear. 

Toxicology of Lead Salts. — In spite of its great frequency, 
lead-poisoning rarely figures in the courts, owing to the fact that 
most of the cases are due to slow absorption of minute quantities, 
exposure to which is an incident of certain industries dealing with 
lead or its compounds. The fatal cases represent but a small 
fraction of the persons who, from numberless causes, suffer from 
degrees of chronic poisoning more or less serious, but not ending 
in death. 

Poisonous Salts. — The salt which is of most importance in 
acute poisoning is lead acetate, while chronic poisoning is most 
frequently caused by lead carbonate. 

The subacetate of lead present in Goulard's extract has very 
much the same effect as the acetate, but greater in degree, as it 
contains more lead. Lead chromate (chrome yellow), lead oxids 
(litharge and red lead), and finely divided metallic lead, while not 
soluble in pure water, dissolve in certain natural waters containing 
nitrates and nitrites and in the dilute vegetable acid's of food and 
in the gastric juice, are absorbed in the intestines, deposited in 
various tissues, and exert a slowly cumulative poisonous action. 



324 THE METALS 

Ledoyen's Disinfectant," containing lead nitrate, and "Tur- 
ner's yellow," or the oxychlorid — in fact, all the salts of lead 
are poisonous, except perhaps the sulphid and sulphocyanate. 

Acute Lead-poisoning. — Symptoms. — At first they are such as 
result from a local irritant, and are less likely to be fatal from a 
single large dose than from the same amount taken in fractions 
at intervals. In a few minutes a metallic taste is perceived, and 
soon afterward the mouth and throat feel dry and burn. Retching 
and vomiting may appear in less than half an hour and prove 
obstinate and. persistent. Abdominal pains come on in colicky 
cramps, relieved by pressure. Usually the bowels are consti- 
pated; occasionally the stools are bloody, and at a later date they 
are dark from lead sulphid. The urine is scanty, the face anxious, 
the skin dry, the breath fetid, and the tongue coated. While the 
brain is clear, the involvement of the nervous system is indicated 
by the headache, the pain and cramps in the legs, and the numb- 
ness and local palsies which appear a few hours later. After 
a few days in some cases a blue line is seen on the gums. 

Fatal Dose. — It is not known what single dose of lead acetate 
would prove fatal. Since recovery has taken place in 3 cases 
after taking 1 oz. (28.3 gm.) of the acetate, it would seem that the 
fatal amount must be greater when that salt is the poison. It is 
probable that the fatal dose of the carbonate would be somewhat 
less than that of the acetate, though the course of the symptoms 
would be slower. 

Fatal Period. — While death from the acute form is very rare, 
23 cases have been collected. It may occur from prostration as 
early as the second or third day. 

Treatment. — The first indication is the washing-out of the 
stomach by a tube or pump, using a solution of magnesium or 
sodium sulphate. In the absence of the tube an emetic dose of 
alum (a soluble sulphate) would be serviceable. When the 
stomach is quiet, the remainder of the poison can be neutralized 
and the bowels evacuated by J oz. of magnesium sulphate (Epsom 
salt). To check vomiting and colic the best reliance is on hypo- 
dermic injections of morphin and atropin. 

Postmortem Appearances. — In the few autopsies which have 
been held in acute lead-poisoning indications have been found of 
gastro-intestinal inflammation. When life has been prolonged 
until systemic symptoms appear, lesions have been found in the 
liver and kidneys. 

Chronic Lead-poisoning (Plumbism, Saturnine Intoxication). — 
Judging by the cases reported in the medical journals, chronic 
poisoning is of very common occurrence. In the Vast majority 
the lead enters the body by accident, as a result of its use in cer- 



LEAD 325 

tain industries; in a certain proportion it is caused by contamina- 
tion of food and drink. In these cases the amount of lead in each 
dose is so small as to escape detection, but, owing to its extra- 
ordinary cumulative action, in time a sufficient quantity finds 
lodgment in different organs to produce widespread damage. 

Injurious Industries. — Operatives in the metal are liable to 
have it introduced by inhalation, by dust particles getting in the 
hair, beard, or clothing, and indirectly into food and drink, and 
possibly through the skin. In this way many cases have been 
caused in plumbers, smelters, type-founders, compositors, shot- 
makers, file-cutters, lead-foil workers, etc. It is even more com- 
mon in those who work in the lead salts used for colors, such as 
color-grinders, white- and red-lead makers, japanners, enamelers, 
lapidaries, potters, combers of yarn dyed with chrome yellow, and 
workers on the lead plates of electric accumulators. 

Food Contamination. — As lead is slightly soluble in water con- 
taining certain salts and gases (see p. 321), its widespread use for 
pipes in which beverages are kept standing over night causes it to 
be introduced into drinking water, into ale and beer drawn from 
the cellar, and into seltzer-water kept in siphons. Lead oxid is 
largely used to make a glaze on pottery. From this it may be 
dissolved by acid foods, as fruit jellies, pickles, vinegar, and 
lemon-juice. As a constituent of solder and the alloy used to 
tin iron it finds access to canned goods containing acids. 

As a substitute for the yellow of egg in making sweet cakes, 
lead chromate, PbCr0 4 , under the name " chrome yellow" has 
been used by bakers, with very grave consequences. An epidemic 
of lead-poisoning in the north of France, involving over 100 persons, 
was traced to lead in the flour which was obtained by all the suffer- 
ers from the same mill, contamination being due to the elevator 
buckets, which were " tinned" with lead. 

Cosmetics. — Most of the lotions called " hair-renewers " are 
preparations containing sulphur with lead acetate or calcium 
plumbite. They do not restore the natural pigment, but cause 
the precipitation of black lead sulphid in the hair structure, so 
as to simulate the natural color. The use of " flake white" as a 
cosmetic has caused every form of chronic lead-poisoning. 

Symptoms of Chronic Lead-poisoning. — In this condition there 
are emaciation, a feeling of "poor health," feeble appetite, im- 
paired digestion, weakened energies, low spirits, and more or less 
profound anemia, as shown by the pallor. The most characteristic 
symptoms are weakness of the forearms with dropping of the wrists 
("the dangles"); colic with constipation ("dry belly-ache"); a 
blue line on the gums and blue patches on the cheeks opposite; 
headaches; joint pains which may be mistaken for rheumatism or 



326 THE METALS 

gout; melancholia or mania; convulsions, sometimes classed as 
epileptic. Albumin in the urine points to the kidneys as the seat 
of serious chronic disease caused by the lead. The blue line on 
the gums is caused by the reaction between lead albuminate in the 
gum and hydrogen sulphid of decomposed food particles between 
the teeth. The formation of the black sulphid is explained by 
this equation: 

PbCl 2 + H 2 S = 2HCI + PbS. 

The black deposit seen through the opalescent mucous mem- 
brane has a bluish color. Lead is found in the urine of most cases 
examined. 

The fatal cases are characterized by convulsions due to brain 
disease. It has been suggested that the gravity of the nervous 
phenomena in poisoning from lead chromate is due in some degree 
to the chromium present in the poison. 

Lead appears to form some stable combination with the sub- 
stance of the nervous system, and induces thereby disturbed func- 
tion, if not local destruction, of some essential part of the great 
centers, as well as of the peripheral nerves. In a case of fatal 
lead-poisoning the cerebrum was found to contain lead equivalent 
to ii gr. of sulphate and the cerebellum about J gr. An optical 
neuritis may cause visual disturbances, but these are sometimes 
due to the retinitis secondary to the kidney mischief. 

Treatment of Chronic Poisoning. — By careful inquiry the source 
of the lead may be discovered, and the patient should be guarded 
against further exposure to it. In the case of operatives in lead- 
works, emphasis must be laid upon the necessity of grinding the 
pigments under water to prevent the fine particles escaping as 
dust into the air; free ventilation is requisite; the hands, nails, 
and beard should be washed and brushed carefully before eating, 
and meals should not be taken inside the factory. A weak lem- 
onade of sulphuric acid is sometimes used as a beverage. Its 
antidotal power may be reinforced by occasional doses of mag- 
nesium sulphate. 

It is well to begin treatment with some magnesium sulphate as 
an antidote to any lead present in the alimentary tract; colic will 
call for morphin and atropin administered hypodermically; joint- 
pains for local fomentations; paralysis for electricity and massage. 
The natural process of elimination of lead is deliberate. It 
escapes slowly by the urine, and five to ten times as much by 
the bowels, without the use of any special eliminant. Several 
special eliminants, notably potassium iodid, have been given freely 
without causing any increase in the amount of lead excreted. 



LEAD 327 

Careful quantitative tests prove that a slight increase attends the 
use of hot baths, general massage, and occasional purgation. 
These last, combined with open-air exercise and wholesome diet, 
are the means most to be relied on. If potassium iodid is given, 
care should be taken that it does not increase the anemia. A 
remission should be allowed, during which iron preparations 
would be of service. 

Postmortem Appearances. — In chronic cases the pathologic 
changes discovered cannot be called characteristic. Where 
albuminuria has been present, the kidneys are found hard and 
contracted, the seat of granular degeneration. When colic has 
been a conspicuous symptom a portion of the intestines has been 
found constricted, with a gray-black discoloration of the mucous 
lining. When there has been local paralysis with atrophy the 
muscles involved have been found wasted and fatty, and changes 
have been discovered in the large cells in the anterior cornua of 
the cord and in the peripheral nerve-fibers. The blue line around 
the gums is highly significant. 

Distribution in the Tissues. — In examining the bodies of 
2 cases suddenly fatal, Blyth separated from the brain of one an 
appreciable amount of lead, from the liver an amount equivalent to 
I gr. of sulphate, from one kidney about ys g r - ln a dog killed by 
chronic lead-poisoning, in parts per thousand, the bones were 
found to contain 0.18 to 0.27; the kidneys, 0.17 to 0.20; liver, 
0.10 to 0.33; spinal cord, 0.06 to 0.11; brain, 0.04 to 0.05; mus- 
cles, 0.02 to 0.04; intestines, 0.01 to 0.02, and traces were detected 
in the spleen, blood, and bile. 

It is a remarkable fact that lead is frequently found in the cadav- 
ers of persons who in life were free from all symptoms of lead- 
poisoning. A fallacious conclusion may be reached if the con- 
tents of the stomach should contain a bit of melted solder from 
a fruit can or a shot derived from eating game. 

In the absence of characteristic symptoms during life, if the 
amount of lead separated from the tissues should be small, it 
should not be regarded as significant of lead-poisoning. 

Lead in the Urine. — From a case which had symptoms so 
vague as to make the diagnosis of lead-poisoning doubtful there 
was obtained from 400 c.c. (14 fl. oz.) of urine as much as 5.2 mg. 
(0.08 gr.) of metallic lead. Elimination is not always uniform. 
For a long time the urine is free from lead and later shows it, 
without further administration in the meantime. 

There is reason to believe that lead is not an uncommon con- 
stituent of the urine. Urine analyses for lead were made in 86 
cases, in the healthy and the sick, with the result of finding lead 
present in 48 cases. Most of them were chosen because of their 



328 THE METALS 

exposure to lead by occupation or otherwise, and, so far as these 
figures are a guide, in not more than 50 per cent, of the community 
at large can lead be detected in the urine. The urines of persons 
known to be in perfect health were almost all free from lead. 

Tests. — Hydrogen Sulphid. — A stream of this gas passed 
through a lead solution, neutral, alkaline, or slightly acid, yields 
a black precipitate of lead sulphid, insoluble in the alkaline hy- 
droxids or the moderately dilute acids. If the amount of metal 
be very small, the precipitate will be brown. Hot nitric acid 
converts it into soluble lead nitrate and free sulphur separates; 
by continued heat the acid converts the sulphur into sulphuric 
acid, and this precipitates the lead as lead sulphate. A small 
amount of lead would remain in solution. 

Fallacies. — This reagent gives a like precipitate with several 
other metals, such as copper and mercury. To distinguish the 
lead the sulphid may be dissolved in warm dilute nitric acid, 
filtered, the filtrate evaporated to dryness to expel any excess of 
nitric acid, the residue taken up with water, and the clear solu- 
tion tested, as stated below, with potassium iodid, dilute sulphuric 
acid, or potassium chromate. If the quantity of the precipitate 
be large, it can be reduced to metallic lead by the blowpipe or 
charcoal. 

Delicacy. — From a solution containing 25 q 00 gr. of lead oxid 
to 10 gr. of water this test gives a faint brownish tint with per- 
ceptible cloudiness. 

Potassium Iodid. — This reagent gives, with very small amounts 
of lead, a yellow coloration; with larger amounts, a yellow pre- 
cipitate of lead iodid, soluble in boiling water, from which it 
deposits, on cooling, in gold-colored hexagonal scales. 

Fallacies. — If the lead be small in amount and has been treated 
previously with nitric acid, a brownish color will be caused by the 
iodin freed from the potassium, unless the free nitric acid has been 
neutralized or driven off by heat. Lead iodid is soluble in potas- 
sium hydroxid and in strong hydrochloric acid. 

Delicacy.— A very small quantity of the reagent will cause a 
satisfactory deposit of small plates from a solution of -2 0000 g r - 

Sulphuric Acid. — This reagent, diluted, gives a white crys- 
talline or granular precipitate of lead sulphate, which is favored 
by the addition of alcohol. The precipitate is soluble in hot strong 
hydrochloric acid, in ammonium acetate, and in a large excess of 
potassium hydroxid. 

Fallacies. — This reagent will also make a white precipitate with 
barium and strontium salts, and with fairly strong solutions of 
calcium compounds. The lead sulphate is characterized, how- 
ever, by turning black with ammonium sulphid. 



LEAD 



329 



Potassium Chromate or Dichromate. — Either of these 
reagents precipitates lead as a yellow amorphous deposit soluble in 
potassium hydroxid and strong hyrochloric acid, but insoluble in 
acetic acid. A yellowish precipitate produced by potassium chro- 
mate in neutral copper solutions dissolves in acetic acid and is 
thus readily distinguished from the lead precipitate. 

Detection in Gastric Contents, Tissues, etc. — A method 
suitable for the urine, feces, gastric contents, or the finely divided 
viscera is the evaporation of the fluid or the dilution of the solids 
to the consistence of a gruel, the destruction of organic matter with 
potassium chlorate and hydrochloric acid (see p. 283), and filtra- 
tion while hot. While some of the lead is apt to remain as insol- 
uble sulphate on the filter, a considerable quantity in a soluble 
combination with potassium chlorid passes through. In toxico- 
logic analysis, as a rule, the total amount of lead is not in excess 
of what will be dissolved. The filtrate may be precipitated with 
hydrogen sulphid, the precipitate dissolved in warm dilute nitric 
acid, the solution filtered and evaporated to dryness, the residue 
redissolved in water, and tested with sulphuric acid or potassium 
iodid. 

Detection in Urine. — The following method for the urine is 
very delicate: A quart of urine acidified with acetic acid is evap- 
orated to dryness and fused in a crucible with a little pure niter 
until it becomes white. When the crucible is cool, dilute hydro- 
chloric acid is added hot to extract the residue after ignition. 
The extract is then filtered, and the filtrate treated with ammonium 
to alkaline reaction, to precipitate the phosphates and iron. Am- 
monium sulphid is added at the same time to throw down the lead 
and iron as sulphids. This deposit is washed three times by decan- 
tation with hot water; then water acidified with hydrochloric acid 
is added, and the whole allowed to stand until the next day. It 
is then filtered through a small filter and the residue washed. A 
little pure nitric acid is then added, drop by drop, to dissolve the 
lead sulphid left on the filter and carry it through as nitrate. 
This filtrate is collected in a watch-glass, evaporated to dryness, 
and the final test made by adding a drop of water and a crystal 
of potassium iodid. A yellow precipitate denotes lead. 

Electrolysis. — To electrolyze the filtrate of the hot decoction 
with potassium chlorate and hydrochloric acid it is placed in a 
glass vessel with a bottom of parchment-paper. This cell is im- 
mersed to the surface level in an outer vessel containing distilled 
water acidulated with sulphuric acid. In the inner cell is placed 
the cathode of four Grove cells in the shape of platinum foil 
50 cm. square (2 in. by 4 in.). Beneath the parchment diaphragm, 
near to it and parallel with the cathode on the opposite side, is 



330 THE METALS 

placed the anode. In six hours the cathode is removed, washed, 
dried, and cleaned of its lead with warm dilute nitric acid. After 
driving off the free nitric acid by heat the lead is precipitated by 
dilute sulphuric acid and an equal volume of alcohol added. 
After being set aside for twenty hours the precipitate is washed 
free from acid with water containing 12 per cent, of alcohol. 
Decanted, ignited, and weighed, 100 parts of the sulphate equal 
68.319 parts of metallic lead. 

Quantitative Determination. — While the electrolytic method 
is preferable when the amount of lead is small, for large quantities 
it is better to precipitate the lead dissolved by decoction in hot 
hydrochloric acid with hydrogen sulphid. The precipitate may 
be converted into sulphate by treating it first with warm dilute 
nitric acid, nitrating, evaporating, dissolving in water, and pre- 
cipitating with sulphuric acid, evaporating, igniting, and weighing 
as above, calculating 68.319 parts of lead for 100 of the sulphate. 

BISMUTH 

Symbol, Bi. Atomic weight, 208.3. 

Occurrence. — The metal occurs free in nature and also as a 
sulphid. From this sulphid it is obtained by first roasting until 
it is converted to oxid, and then reducing the oxid with carbon. 

Properties. — Bismuth is a reddish-white, brittle, crystalline 
metal. Its crystals are isomorphous with arsenic and antimony. 
It is unchanged by air or water, and is a good conductor of elec- 
tricity. Its ion is the trivalent bismuthion, Bi*". It forms some 
alloys that melt below the boiling-point of water. 

Rose's fusible metal consists of bismuth 2 parts, lead 1, and 
tin 1. It melts at 93. 8° C. (201 F.). 

Wood's metal consists of bismuth 4 parts, lead 2, tin 1, and 
cadmium 1. It melts at 60.5 ° C. (141 ° F.). 

Bismuth sesquioxid, Bi 2 3 , is a yellow powder formed by 
burning bismuth in air. It is also formed when the hydroxid, 
Bi(OH) 3 , is heated and loses water. Both are basic. 

Bismuth hydroxid, Bi(OH) 3 , is precipitated from bismuth 
solutions by excess of alkali. It is an insoluble white powder. 
With nitric acid it forms bismuth nitrate, Bi(N0 3 ) 3 , showing that 
it is a triacid base. By losing the constituents of water, Bi(OH) 3 
changes to bismuthyl hydroxid, BiO.OH, which is a monacid base. 
In reacting with nitric acid the hydroxyl is replaced and bismuth 
oxynitrate or subnitrate, BiO.N0 3 , is produced. A whole series 
of subsalts or basic salts are formed by this univalent group, 
bismuthyl, BiO. 

Bismuth Subcarbonate[(BiO) 2 C0 3 .H 2 5 ] (Bismuthyl Carbonate 



BISMUTH 33I 

Oxycarbonate) . — This is formed when a solution of the normal 
nitrate is treated with sodium carbonate. Carbon dioxid is 
given off, and the subcarbonate is precipitated as a yellowish- 
white insoluble powder. When heated, water and carbon dioxid 
escape, leaving bismuth oxid, Bi 2 O s . 

Dose: 10 to 60 gr. (0.666-4 gm.). 

Bismuth Subnitrate (BiO.N0 3 .H 2 0) (Bismuthyl Nitrate, Oxy- 
nitrate). — When bismuth is dissolved in nitric acid a clear solution 
of the normal nitrate, Bi(N0 3 ) 3 , is obtained. By pouring this 
solution into water a heavy white precipitate of bismuthyl nitrate 
forms, and some nitric acid is left, possibly in combination with 
bismuth: 

Bi(N0 3 ) 3 + 2 H 2 = BiON0 3 .H 2 + 2HNO3. 

Dose: 10 to 60 gr. (0.666-4 g m 0- 

Incompatibles. — Tannic and gallic acids; calomel; sulphur; 
salicylic acid; potassium iodid; with alkaline bicarbonates it 
causes effervescence. 

Nylandefs reagent is an alkaline solution of bismuth hydroxid 
by means of sodium potassium tartrate (p. 603). When boiled 
with a glucose solution the reduced metal bismuth is precipitated 
gray or black. 

Bismuthi et ammonii Cltras (U. S. P.) is of indefinite com- 
position. The ordinary citrate of bismuth, BiC 6 H 5 7 , is a white 
insoluble powder which in ammonium hydroxid becomes soluble. 
This double citrate forms small pearly scales which are soluble 
in water. Dilute acids change it to the insoluble form. Dose: 
1. to 5 gr. (0.066-0.33 gm.). 

Other official compounds of bismuth are Bismuthi citras, dose, 
2 gr. (0.125 gm.); bismuthi subgallas, dose 4 gr. (0.250 gm.) and 
bismuthi subsalicylas, dose 4 gr. (0.250 gm.). 

Toxicology. — The study of the toxic action of bismuth is 
practically that of the salt most commonly used in medicine, the 
subnitrate. This white, odorless, almost tasteless, and nearly 
insoluble powder, is sometimes used as a cosmetic under the name 
of " pearl white." It is much esteemed as a local sedative for 
gastric and intestinal irritation and is given almost ad libitum. 
At one time most samples were imperfectly freed from the arsenic 
which is found associated with bismuth in its ores. Antimony, 
lead, and a trace of tellurium have been found in it. At present, 
contaminants are rarely detected, owing to the more perfect 
methods of preparation now employed. Owing to its difficult 
solubility, the pure subnitrate in any but very large doses has no 
toxic action. When applied to open wounds and extensive burns 



332 



THE METALS 



as an antiseptic, some absorption is apt to occur with symptoms 
of systemic poisoning. 

Symptoms. — While the salt itself has only a feebly acid taste, 
yet in cases of poisoning from absorption a peculiar metallic taste 
is complained of, accompanied by salivation, foul breath, and sore 
mouth. There are vomiting, abdominal pain, and purging of 
stools, dark from bismuth sulphid. Sometimes a black discolora- 
tion appears upon the gums, but may spread over the whole mouth. 
The reaction of the hydrogen sulphid generated from decom- 
posed food with bismuth nitrate is as follows: 

2Bi(N0 3 ) 3 + 3H 2 S = Bi 2 S 3 + 6HN0 3 . 

The black Bi 2 S 3 is insoluble in ammonium sulphid, which thus 
separates it from the sulphids of arsenic and antimony. 

The strong garlicky odor of the breath sometimes observed 
has been attributed to tellurium, which produces this effect, 
although the amount is very minute. As the gastro-enteric 
symptoms are similar to those of arsenic, the toxic action of bis- 
muth was at one time ascribed to that impurity. Large doses 
internally, as well as free topical applications of bismuth salts, 
have in some cases caused black urinary sediment, albuminuria, 
and tube-casts, beside the usual stomatitis, loosened teeth, blue 
gingival line, diarrhea, and ulceration of the intestines. 

Cases have been described which show peculiar effects on 
the mouth when the bismuth salt has been absorbed at distant 
points, due to the fact that bismuth is eliminated largely by the 
saliva. These cases are remarkable because equally large amounts 
have been administered by the mouth without injurious con- 
sequences. In one case an extensive burn was treated with 
local applications of bismuth subnitrate, proved by analysis to be 
pure. In two weeks there was a severe inflammation of the 
mouth and throat with adherent black exudations; vomiting and 
diarrhea supervened with albuminuria. Bismuth was detected 
in the urine and the feces. A few days after the application was 
discontinued the acute symptoms subsided. 

An experimental research on the lower animals, using a pure 
salt of bismuth hypodermically, caused death after symptoms 
like those just described. 

Fatal Dose. — The earlier reports as to the fatal dose must be 
taken with much allowance, owing to the fact that until recent 
times the bismuth salts almost always contained enough arsenic 
to cause trouble if the dose was a liberal one. Death has fol- 
lowed a dose of 2 dr. The period of fatality was the ninth day. 
A dose three times as large has been recovered from. 



SILVER 333 

Tests. — Hydrogen sulphid yields a black precipitate of bis- 
muth sulphid. If this is dissolved in the smallest possible quan- 
tity of hot nitrohydrochloric acid and the resulting solution poured 
into an excess of water, a copious white precipitate of bismuth 
oxychlorid is thrown down. 

Extraction from the tissues is done by boiling the finely 
divided matter for two hours in dilute nitric acid, the dissolved 
material separated by filtration, and the filtrate evaporated to 
dryness. The undissolved organic matter is destroyed with 
strong nitric acid and then boiled with dilute nitric acid, filtered, 
and dried. 

A solution of both residues is made in 50 per cent, nitric acid 
and the above tests are applied. 

SILVER (Argetitum) 

Symbol, Ag. Atomic weight, 107.66. 

Occurrence. — Metallic silver is sometimes found free in nature. 
Its chief ore is a sulphid which also contains lead sulphid. Lead 
and silver are extracted together and roasted in air. The lead 
oxidizes to litharge, but silver retains its metallic character, even 
at a high heat, like the other noble metals. 

Properties. — Silver is tenacious, pure white in color, and 
maintains the highest luster, resisting perfectly the action of oxy- 
gen and water vapor. By air containing a trace of hydrogen 
sulphid and by other sulphids and organic-sulphur compounds, 
silver is blackened with a film of sulphid. It has a specific gravity 
of 10.5, is the best conductor of electricity and heat, and melts at 
1000 C. (1832 ° F.). When the metal is precipitated in the 
metallic state by reduction from the solutions of its salts, it is 
not white, like the normal form, but may be yellow, brown, gray, 
or black. When reduced from alkaline solutions it assumes 
a suspended condition of a red or brown color; and when dry 
takes on a metallic luster and any one of several colors — yellow, 
green, red, or violet. These are considered to be allotropic 
forms. 

Colloidal Silver. — In the presence of organic compounds like 
gelatin, casein, citric acid, etc., reducing agents act without pre- 
cipitation. The result is an olive-brown, stable solution which 
should not be exposed to light or air. This colloidal silver differs 
from metallic silver in being apparently soluble in water, yet it 
dissociates very little argention for the reaction with chloridion. 
Though it is bactericidal and used as a surgical antiseptic, it does 
not permeate membranes. The only difference between this 
colloidal solution and a true suspension is that of size of the sus- 



334 THE METALS 

pended particles. Those of the colloidal solution are so small that 
by friction on each other they are kept suspended and free from 
gravitation tendency. The ultramicroscope, by intense oblique 
illumination, makes the particles visible like those of dust floating 
in the air when illuminated by a sunbeam. 

By its luster and rarity silver commends itself for precious 
coins, but because of its softness it is not fit for any rough use 
until alloyed with about 10 per cent, of copper, which makes it 
harder. From coins pure silver is obtained by first dissolving in 
nitric acid, which takes up both silver and copper and precip- 
itates the silver with sodium chlorid, leaving the copper nitrate in 
solution. Silver chlorid, dried and heated in a crucible with, 
sodium carbonate, yields the silver as a metallic button, the chlorin. 
going to the sodium to form sodium chlorid and carbon dioxid. 
escaping as vapor. 

Silver is not affected by the strongest alkalis, nor by any dilute- 
acid except nitric. It is soluble in nitric and sulphuric acids and 
solutions of potassium cyanid. 

The Ion of Silver. — Argention, Ag*, is univalent and colorless. 
Its hydroxid is strongly basic, like the alkalis, forming soluble 
salts that are neutral. The ion passes into the metallic state with, 
great readiness. Its salts in contact with organic matter, stimu- 
lated by sunlight, separate the finely divided metal of a brown or 
black color. Metallic silver is not poisonous, as is often demon- 
strated by the use of silver wire in closing wounds by suture, and 
the absence of injurious consequences when silver coins have been 
swallowed accidentally. But argention is an active poison. It 
is, however, a reagent for precipitating halogens, and, owing to. 
the wide distribution of the chloridion of common salt in the 
tissues, the argention is quickly thrown out of action and then 
reduced to the metallic state as a permanent deposit. 

Silver Oxid (Ag 2 0) (Argenti Oxidum). — There are three oxids. 
of silver: Ag 4 0, AgO, and Ag 2 0. The last is called normal, and 
is the only one of medical interest. At ordinary temperature the 
alkaline hydroxids precipitate from solution of silver nitrate this, 
normal silver oxid, Ag 2 0. It is a brown powder of slight solu- 
bility, but sufficient to give an alkaline reaction. Dose: J to J gr. 
(o.on-0.016 gm.), best mixed with chalk and given in capsules. 
It is incompatible with ammonia, phosphorus, organic matter, and 
the salts of mercury, iron, bismuth, and copper. 

Silver Chlorid (AgCl) {Argenti Chloridum).— This is the white- 
precipitate formed when the ions of silver and chlorin meet. 
A white powder, it turns gray and violet on exposure to light,, 
the darkening being due to change of AgCl 2 to the subchlorid,. 
Ag 2 Cl, and free chlorin; it is in proportion to the intensity of the: 



SILVER 335 

light. While very sparingly soluble in water silver chlorid dissolves 
in ammonia, the thiosulphates, and potassium cyanid. 

Silver bromid, AgBr, is obtained as a fine yellowish precipi- 
tate when argention and bromidion are brought together. It 
resembles silver chlorid, but is much less soluble in ammonia, 
though soluble in thiosulphates. It is more sensitive to light 
than the chlorid. 

Bromid-gelatin plates for photography are prepared by adding 
ammonium bromid to solution of gelatin, and in the dark adding 
silver nitrate. Silver bromid is precipitated in a finely divided 
state, embedded in the gelatin: 

AgX0 3 + XH 4 Br = XH 4 X0 3 - AgBr. 

By washing the cooled mass the excess of ammonium bromid 
and the ammonium nitrate are removed. When warmed, the 
sensitive gelatin melts and is applied as a thin film to glass or 
celluloid. Such a plate in the focus of a camera has its silver 
bromid reduced to sub-bromid in proportion to the light coming 
from the object. 

Developers. — The process of reduction is completed by im- 
mersing the plate in a reducing liquid called a developer. The 
developer is a solution of ferrous sulphate, pyrogallic acid, potas- 
sium ferro-oxalate, etc. Metallic silver is deposited in proportion 
to the intensity of the light that made the initial reduction. The 
lights of the picture have caused a dense precipitate, the shadows 
little or none. At a satisfactory point in development the plate 
is washed free of silver bromid by sodium thiosulphate, or hypo, 
and there remains a fixed negative — that is, a picture which re- 
verses the lights and shadows. 

Silver Nitrate (AgXO s ) (Argenti Xitras, Lunar Caustic). — 
Concentrated nitric acid dissolves pure silver, and on evaporation 
leaves colorless crystalline plates. These are readily soluble, 
have a metallic taste, and are stable apart from organic matter, 
but with it they blacken by reduction to metallic silver. It forms 
insoluble compounds with albumin, and hence is a superficial 
caustic, producing a shallow eschar, which soon blackens. This 
quality makes it useful as a hair dye and an indelible ink. To 
obviate brittleness the crystals are melted with 4 per cent, hydro- 
chloric acid and cast in sticks called argenti nitras /usus. For 
mild local use stick caustic is sometimes diluted with potassium 
nitrate, making mitigated nitrate, argenti nitras mitigatus, U. S. P. 
The incompatibles are alkalis, alcohol, chlorids, acetates, bromids, 
iodids, carbonates, cyanids, arsenites, salts of antimony, copper 
and manganese, vegetable extracts, phosphates, sulphids, tannic 
acid, and vegetable astringents. 



336 THE METALS 

Silver cyanid, U. S. P., (AgCN), is precipitated as a white 
solid when argention meets cyanidion (CN)': 

Ag«, (NO s )' + K% (CN)' = K-, (NO s )' + AgCN. 

By adding excess of potassium cyanid a soluble double salt 
is formed: 

AgCN + K V (CN)' = K-, [Ag(CN)J. 

This solution fails to give the ordinary silver reactions because 
it has no argention, the metal being locked up in the silver cyanidion 
[Ag (CN) 2 ] / . In electroplating with this solution the double salt 
breaks down and the silver goes to the object at the negative pole 
to be deposited as a uniform metallic coating. 

Toxicology. — Of 7 cases reported due to accidental swallowing 
of the caustic when applied to the throat for local affections, 5 
were in children (1 of these was fatal) and 2 in adults. 

Symptoms. — The contact of the caustic causes instant pain in 
the throat and stomach, prompt emesis, and later purging of 
bloody matters. After absorption takes place, nervous symptoms 
supervene, such as vertigo, spasms, disturbed respiration, and 
coma. 

Chronic Poisoning. — Repeated cauterization with silver nitrate 
caused the following effects: Emaciation, followed in a few weeks 
by paralysis and other nervous affections, with ecchymoses under 
the eyelids. The face turned a leaden color, the sclerotics were 
discolored, many brown-black spots appeared all over the body, 
and a blue line was seen on the gums. Similar discoloration 
patches, oval and about the size of apple seeds, have been found 
in silver workers, and are attributable to absorption through 
abrasion of the hands. The patches proved to be due to deposit 
of metallic silver in the tissues. 

A leaden-bluish discoloration of the face and possibly of other 
parts of the body is sometimes brought on by the medicinal use 
of small doses of silver nitrate given for a long period. No man- 
ner of treatment is of any avail to remove this discoloration. 

Fatal Dose. — Death has resulted from 30 gr. taken by an adult. 

Fatal Period. — In six hours after swallowing a piece of " lunar 
caustic" a child of fifteen months died in convulsions. 

Treatment. — Large drafts of common salt and water will favor 
vomiting and at the same time be the best antidote, forming insol- 
uble silver chlorid. The stomach-pump may be used, if necessary. 
This treatment can be followed up with a diet of eggs and milk. 

Postmortem Appearances. — The local action of the caustic 
will be seen in stains, at first white, and on exposure to light, 



iron 337 

turning black. These stains are found on the lips, in the mouth, 
on white clothing, and on the mucous membrane of the digestive 
tract touched by the poison. Gastro-intestinal inflammation is 
present. 

Tests. — Hydrochloric acid and soluble chlorids precipitate 
from soluble salts of silver, white-silver chlorid, insoluble in nitric 
acid, but readily soluble in ammonia-water and in potassium 
cyanid. 

Hydrogen sulphid or ammonium sulphid precipitates a dark 
brown silver sulphid in accordance with this equation: 

2 AgN0 3 + HS = Ag 2 S + 2HNO3. 

Potassium iodid gives a yellow precipitate, and potassium 
chromate a blood-red precipitate. 

Extraction from Stomach Contents. — Finely divided tissues 
or gastric contents are digested with ammonia and potassium 
cyanid. The decanted fluid is treated with excess of hydrochloric 
acid and the insoluble chlorid separated by decantation; the pre- 
cipitate is washed on a filter with hot water, dried, and reduced on 
charcoal to metallic silver. 



VL— THE IRON GROUP 

This group includes iron, cobalt, nickel, manganese, zinc, and 
chromium, heavy metals whose sulphids are insoluble in water, 
but are soluble in dilute acids. 

IRON (Ferrum) 

Symbol, Fe. Atomic weight, 56. 

Iron is the most important of the metals, because of the abun- 
dance of its ores, the ease of its extraction, and the value of its 
properties. 

Occurrence. — Iron ranks next to aluminium in abundance in 
the crust of the earth. Rarely it occurs free in nature in two 
forms, meteoric and telluric. The metal of fallen meteorites is 
never pure, as it contains cobalt, nickel, and other metals. The 
telluric kind is found in small quantities in lavas and basalt. 
Its most common ores are oxids, such as magnetic oxid, Fe 3 4 ; 
red hematite, Fe 2 3 ; carbonate, FeC0 3 ; and sulphids or iron 
pyrites, FeS 2 ; magnetic pyrites, FeS 4 ; copper pyrites, Fe 2 S 3 . 

Nearly all rocks contain silicate of iron, which, decomposing to 



338 THE METALS 

oxid, imparts a red color to the soil. Plants absorb the iron and 
store it in the green chlorophyl of leaves, which is essential to 
the interaction of carbon oxid, water, and oxygen, by which the 
tissues are built up. Having served the respiratory function of 
the plant, iron is assimilated by animals from their vegetable food, 
stored in the liver as a loose compound called jerratin, from which 
it is taken as required to become a necessary constituent of the 
hemoglobin which carries the oxygen of respiration to the animal 
tissues. It is eliminated from the body as a constituent of bile 
coloring-matter. In animals and plants its physiologic impor- 
tance appears to be due to a catalytic influence exerted, by which 
it accelerates the oxidation processes. 

In extracting the metal from its carbonate, sulphid, and hy- 
droxid the ore is roasted in air, evolving from sulphids, S0 2 ; 
carbonates, C0 2 ; hydroxids, steam; all of these escaping as gases. 
From the oxid simple reduction with carbon suffices: 

Fe0 4 + 4 C = 4 CO + 3 Fe. 

Limestone or sand and feldspar are also heated with the ores 
in order to take up impurities and protect the metal when it is 
freed. As molten metal it is received in molds in sand. This 
crude pig iron always contains some carbon, silicon, sulphur, 
phosphorus, and other impurities. Cast iron contains about 5 
per cent, of carbon. It melts at a lower temperature than pure 
iron, is not so hard as steel, and is more brittle than wrought 
iron. By melting again and blowing in air some of the carbon, 
phosphorus, sulphur, etc., is burned out and a purer product 
obtained called wrought iron. This is tough, strong, malleable, 
and ductile, and contains less than 0.5 per cent, of carbon. It 
welds easily, but is soft and bends under strain. When cast iron 
is melted and purified by oxidation and then, by the addition of 
iron containing carbon, converted into a product containing 
between 0.8 and 2 per cent, carbon, we have steel. When steel is 
heated and suddenly cooled it becomes extremely hard and brittle. 
If carefully heated and then cooled slowly, it becomes soft and 
elastic. In its soft state steel can be given the shape desired and 
•by tempering at different temperatures the hardness can be regu- 
lated to the degree required for the uses of the instrument. 

Properties. — Pure iron is silver white and susceptible of a 
high polish. It is more malleable, softer, and less tenacious than 
wrought iron. Its specific gravity is 7.84. It melts only at the 
highest temperatures, but at a lower point — about 600 ° C. (1112 
F.) — it becomes plastic like wax, and can be pressed, rolled, forged, 
and welded. In dry air it is unchanged at ordinary temperatures, 



iron 339 

but at a red heat it oxidizes. In moist air it forms a rust of 
hydrate and oxid. Galvanized iron is made so by dipping the iron 
into molten zinc to protect it from moisture. The purest com- 
mercial form is card teeth or piano wire. 

Reduced iron (Ferrum reductum, Quevenne' s iron, iron by 
hydrogen) is prepared by heating the oxid, Fe 2 3 , in a current of 
hydrogen. The hydrogen abstracts oxygen to form water, leaving 
a gray-black powder, odorless, tasteless, and insoluble. Dose: 
i to 5 gr. (0.066-0.333 gm.). Incompatible with potassium chlo- 
rate and permanganate; hydrogen dioxid; salts of antimony, cop- 
per, bismuth, lead, mercury, and silver. 

Iron dissolves in hydrochloric acid, forming a chlorid, and in 
dilute sulphuric acid, forming a sulphate, in each case liberating 
hydrogen. The electric charge of the hydrion has changed the 
iron to ferrion. It unites directly with the halogens, sulphur, 
phosphorus, arsenic, and antimony. When dipped into concen- 
trated nitric acid it becomes passive. Some electric condition is 
induced which protects it from further action by either dilute or 
strong nitric acid. 

Ferrous and Ferric Ions. — There are two kinds of elementary 
ions formed by iron, one divalent, dijerrion, the other trivalent, 
triferrion. The compounds of the former are similar to those of 
magnesium and are called ferrous; those of the latter resemble 
aluminium salts and are called ferric. Diferrion has an inky 
taste and is colorless, but in aqueous solution forms greenish fer- 
rous hydroxid. It has a tendency to pass into triferrion, also 
colorless, but in water forming brown ferric hydroxid. This 
brown hydroxid is in colloidal solution, having been split off 
from the ferric salt by hydrolytic dissociation. When diferrion, 
Fe", changes to triferrion, Fe*", by the action of oxidizing agents 
it receives an additional ionic charge which, under favorable con- 
ditions, it surrenders to reducing agents, passing back to the 
divalent form, Fe". The effect of exposure of a ferrous solution 
to the air is to cause oxygen and water to form hydroxidion, the 
negative ion needed to give to diferrion its increased positive 
charge. The change takes place in the sense of the following 
equations: 

3FeCl 2 + O + H 2 = 2 FeCl 3 + Fe(HO) 2 

Ferrous chlorid. Ferric chlorid. Ferrous hydroxid. 

The ferrous hydroxid with the co-operation of water takes more 
oxygen and forms the ferric hydroxid: 

2 Fe(HO) 2 + O + H 2 = 2 Fe(HO) 3 

Ferrous hydroxid. Ferric hydroxid. 



340 THE METALS 

Ferrous Chlorid (FeCl 2 ) (Iron Protochlorid).— When iron is 
heated in a current of dry hydrochloric-acid gas a white salt is 
obtained. This anhydrous compound takes up 4 parts of water 
of crystallization, turning green in color. When excess of iron 
is dissolved in hydrochloric acid a pale green solution of the 
ferrous chlorid is formed. The dissociation of ferrous chlorid in 
solution is represented thus: Fe*% CI', CI'. When chlorin is 
passed into the solution the cation Fe" takes a third ionic charge, 
the chlorin neutral atom changing to the anion chloridion: 

Fe-Cl', CI', + CI = Fe-Cl', CI', CI'. 

This is an illustration of the fourth mode of ion formation; where 
an atom changes to an ion, at the same time giving an additional 
charge of electricity to an ion already present. It is called oxida- 
tion in the sense that it increases the electric charges of an ion; 
whereas reduction diminishes the charges. When the above 
equation is reversed it represents reduction. 

Ferric Chlorid (Fe0 3 ,6H 2 0) (Ferri Chloridum, Sesquichlorid, 
or Perchlorid). — The pharmaceutic product is prepared by adding 
to a solution of ferrous chlorid nitric and hydrochloric acids with 
heat. Fumes of nitrogen dioxid are formed: 

FeCl 2 + HNO3 + HC1 = FeCl 3 + H 2 + N0 2 . 

On evaporation the ferric chlorid is obtained as an orange-yellow 
deliquescent mass of acid reaction and strongly styptic taste. 

The pure anhydrous ferric chlorid is obtained as a sublimate 
of dark green crystals when iron is heated in a current of chlorin. 
They dissolve in water with a rise of temperature yielding a yellow- 
brown solution from which the anhydrous salt cannot be again 
obtained. By evaporation yellow hydrates crystallize which by 
heat decompose to HO and Fe(HO) 3 . 

In the presence of substances which oxidize readily, such as 
morphin, ferric chlorid decomposes water, sets free available 
oxygen, and is itself reduced to ferrous chlorid thus: 

2 FeCl 3 + H 2 = 2 FeCl 2 + 2HCI + O. 

Liquor ferri chloridi is an aqueous solution of ferric chlorid 
containing 37.8 per cent, of anhydrous salt with some free hydro- 
chloric acid. It is a reddish-brown, acid, astringent liquid of a 
specific gravity of 1.405. 

Tinctura ferri chloridi (muriated tincture oj iron) is prepared 
by mixing the above solution with 3 volumes of alcohol and keeping 



IRON 341 

in a stoppered bottle for three months. From the alcohol certain 
ethereal compounds are produced which impart to the acid brown- 
ish liquid their odor, taste, and medicinal effect. It contains 
13.28 per cent, of FeCl 3 . This is a valuable ferruginous tonic, 
which should be taken freely diluted in water, syrup, or glycerin, 
and through a tube to prevent action on the teeth. Dose: 5 to 
20 tit (°-33~ 1 -33 c.c.). Its incompatibles are mucilage of acacia, 
astringent infusions and tinctures, tannic acid, antipyrin, and 
alkalis and their carbonates. 

Ferric Hydroxid {Ferric Hydrate, Ferri Oxidum Hydratum). — 
When alkaline bases are added to solutions of ferric salts, a brown, 
flocculent, gelatinous precipitate of ferric hydroxid is obtained: 

FeCl 3 + 3 NaHO = Fe(HO) 3 + 3 NaCl. 

The fresh hydroxid is soluble in acids and in solution of ferric 
chlorid. On standing it assumes less soluble forms, growing denser 
and to some extent giving up the constituents of water, thus: 

2Fe(HO) 3 = Fe 2 3 + 3H 2 0. 

When freshly precipitated and strained off in a state of loose 
magma it is an efficient antidote to arsenic, but the anhydrid 
change that occurs in time lessens materially its virtue in this 
respect: 

Fe(HO) 3 + H 3 AsO s = FeAs0 3 + 3H 2 0. 

Arsenous acid. Ferric arsenite. 

Ferri Hydroxidum cum Magnesii Oxido (U. S. P.). — This 
is made by mixing, when required, an excess of calcined magnesia 
with solution of ferric sulphate: 

Fe 2 (SOJ 3 + 3 MgO + 3 H 2 = 2 Fe(HO) 3 + 3 MgS0 4 . 

The whole mixture of ferric hydroxid, magnesium sulphate, and 
some excess of magnesium oxid is of service and may be given 
immediately without straining. 

Dialyzed Iron (Ferritin Oxydatum Dialysatum). — This is a 5- 
per cent, solution of colloidal ferric hydroxid once used in medicine. 
It is prepared by adding ammonium hydroxid to a concentrated 
solution of ferric chlorid. The ferric hydroxid first formed dis- 
solves in the ferric chlorid when shaken. This saturated solution 
of basic oxychlorid of iron is put in a dialyzer having a partition 
of parchment-paper, and floated on water. The ammonium 
chlorid quickly diffuses into the water, which is frequently re- 
newed, until there is no reaction with silver nitrate. There is 
hydrolytic dissociation of part of the ferric oxychlorid into hydro- 



342 THE METALS 

chloric acid which, when split off, passes out through the mem- 
brane, and colloidal ferric hydroxid which remains in the dialyzer 
with some trace of chlorid. In the dialyzer is left a dark red 
colloidal solution (the dialysate), the constituents of which are not 
dissociated, having in that state none of the properties of the ferric 
ion. It instantly separates the insoluble gelatinous hydroxid on 
the addition of an electrolyte, such as alkalis, neutral salts, and 
sulphuric acid (p. 93). 

Ferrous Iodid (Fel 2 ). — Elementary iodin in excess and 
metallic iron as card teeth unite directly in the presence of warm 
water, forming a pale green solution. On evaporation greenish 
crystals of ferrous iodid separate. In air the iodid readily decom- 
poses, forming ferric oxid, but if protected by sugar the oxidation 
is prevented. In the following preparations sugar is introduced 
for the purpose of keeping the ferrous salt from changing to ferric 
compounds which have more astringency and irritating quality: 

Pilulae ferri iodidi (Blancard's pills) not only have sugar in the 
pill-mass, but are further protected by a coating of balsam of 
tolu. 

Syrupus ferri iodidi is a syrupy solution of 5-per cent, ferrous 
iodid, transparent, greenish, and neutral. Dose: 5 to 50 TTl (0.33- 
2 ex.). 

Ferrous Sulphid (FeS).— When iron filings and flowers of 
sulphur are heated together a black brittle mass is formed of the 
composition, FeS. Its chief use is in the preparation of hydrogen 
sulphid. As it is readily decomposed by acids, it is not precipi- 
tated when hydrogen sulphid is passed into ferrous solutions. 
The proper precipitant for the iron group is ammonium sulphid, 
which yields black hydrated iron sulphid. Ferrous sulphid in 
the air oxidizes to ferrous sulphate: 

FeS + 4 = FeS0 4 . 

Ferrous Sulphate (FeS0 4 .7H 2 0) (Ferri Sulphas, Copperas, 
Green Vitriol). — The term vitriol is applied to metallic sulphates 
of divalent ions; thus, copper sulphate is blue vitriol and zinc 
sulphate is white vitriol. Ferrous sulphate can be obtained 
by the action of dilute sulphuric acid on iron. The solution 
evaporated yields large pale green prismatic crystals, having 
a styptic taste and acid reaction. In the air it effloresces, absorbs 
oxygen, and partially changes to brown ferric sulphate. It is 
incompatible with vegetable astringents, tannic acid, alkalis, borax, 
lime-water, carbonates, ammonium and calcium chlorid, lead 
acetate, potassium iodid, and nitrate. 

Ferri Sulphas Exsiccatus (FeS0 4 . H 2 0).— Dried sulphate is 
prepared by heating ferrous sulphate at 100 ° C. (212 ° F.) until 



iron 343 

it ceases to lose weight. It is a grayish white powder, useful in 
making pills. Dose: £ to 2 gr. (0.033-0.133 gm.). 

Ferri sulphas praecipitatus, granulated, is ferrous sulphate 
separated as a crystalline powder from solution in weak sulphuric 
acid by mixing with alcohol. It is a convenient form for dis- 
pensing. 

Liquor ferri tersulphatis is a 36-per cent, solution of normal 
jerric sulphate, Fe 2 (S0 4 ) 3 , and is made by heating a solution 
of ferrous sulphate with sulphuric and nitric acids. The nitric 
acid oxidizes diferrion to triferrion. On evaporating and heating 
the residue a yellowish white powder is obtained. Placed in water, 
it at first does not dissolve, but after some time it forms a strong 
brown-red solution. Because of this slow solubility the salt is 
usually kept in the official solution ready made. 

Monsel's salt is a basic, or oxy-, sulphate used in surgery as a 
local hemostatic. It is a yellowish powder obtained by evapora- 
tion from Monsel's solution, which is the official liquor jerri sub- 
sulphatis, containing 43.7 per cent, of the salts. This solution is 
prepared like that of the normal sulphate, but with less sulphuric 
acid. It is supposed to contain ferric hydroxid, Fe(HO) 3 , joined 
to ferric sulphate, Fe 2 (S0 4 ) 3 . It is a dark, reddish brown, highly 
astringent, almost syrupy solution, causing but little local irri- 
tation. 

Ferric Nitrate (Fe(N0 3 ) 3 ). — By dissolving ferric hydroxid in 
nitric acid a solution of this salt results, which when 6 per cent. 
strong is called liquor ferri nitratis. It is transparent, amber 
colored, acid, and styptic. Dose: 5 to 15 Tft, well diluted (0.33- 

1 gm.). 

Ferrous carbonate, FeC0 3 , occurs in nature as "bog ore." 
Insoluble in pure water, it dissolves in natural carbonated waters 
by changing to a soluble ferrous bicarbonate, FeH 2 (C0 3 ) 2 . It is 
formed when alkaline carbonates act on ferrous salts: 

FeSO, + Na 2 C0 3 = Na 2 S0 4 + FeC0 3 . 

The precipitate is whitish green, turning brown-red by oxidation. 
To prevent this change to the ferric condition sugar is used in the 
following official preparations which make use of the same reaction 
as that given above: 

Ferri carbonas saccharatus contains 15 per cent, of FeC0 3 . 
It is a greenish gray powder, sweet and ferruginous in taste. Dose: 

2 to 10 gr. (0.13-0.66 gm.). 

Massa ferri carbonatis (Vallefs mass) contains 42 per cent. 
FeC0 3 . It is unirritating and not astringent. Dose: 3 to 5 gr. 
(0.20-0.33 gm.). 



344 THE METALS 

Mistura ferri composita (Griffith's mixture) contains ferrous 
carbonate suspended in a solution of potassium sulphate with 
sugar and rose-water. Dose: J to i fl. oz. (16-32 c.c). 

Ferrous Phosphate (Fe 3 (P0 4 ) 2 ).— This is formed when 
sodium phosphate is added to ferrous sulphate in the presence of 
sodium acetate. At first white, it absorbs oxygen and soon 
assumes a blue color. It is the source of the slaty-blue color of 
pus and of the lungs in phthisis. 

Ferric phosphate, FeP0 4 , is precipitated when ferric chlorid 
is added to a solution of an alkali phosphate. 

Ferri phosphas (U. S. P.) is a soluble mixture of FeP0 4 with 
sodium citrate. Dose: 5 to 10 gr. (0.33-0.66 gm.). 

Ferri pyrophosphas (U. S. P.) is a soluble mixture in the form 
of scales containing ferric pyrophosphate, sodium citrate, and 
ferric citrate. Dose: 1 to 5 gr. (0.066-0.33 gm.). 

Scale Compounds. — When freshly precipitated ferric hydroxid 
is dissolved in citric, tartaric, or other organic acid, double salts 
are formed of uncertain composition. On evaporating the solu- 
tion the residue is not crystalline. To obtain a convenient form 
for dispensing the solution concentrated by evaporation is spread 
on glass plates and dried at 6o° C. (140 F.). By tapping the 
glass the thin coating is broken into green or brown amorphous 
brilliant scales, which readily dissolve in water. Among the 
scale compounds are soluble iron phosphate, iron and quinin 
citrate, iron and potassium tartrate. 

Iron and Cyanogen.— These two elements do not unite to 
form a simple cyanid, but combine in complex groups which act 
as anions with hydrogen and the metals. As these groups do 
not show the chemical or poisonous properties of cyanids nor 
respond to the usual tests for iron, it is plain that they do not 
contain the ions of cyanogen or of iron. One of these compound 
anions acting like a single element is called ferrocyanogen, and 
its solution becomes ferrocyanidion, Fe(CN) 6 //// . It does not 
exist free, but is supposed to be the constituent anion of hydro- 
jerrocyanic acid, H 4 % [Fe(CN) 6 ] r/// , and enters into the compo- 
sition of metallic ferrocyanids. This tetrabasic acid is prepared 
by the action of strong hydrochloric acid on potassium ferro- 
cyanid. It occurs in white scales, turning blue on exposure to 
the air. 

Potassium Ferrocyanid (K 4 Fe(CN) 6 ) {Yellow Prussiate of 
Potash). — This is prepared by heating together nitrogenous animal 
waste, scrap iron, and potassium carbonate. The permanent 
lemon-yellow crystals are freely soluble and non-poisonous, though 
they form hydrocyanic acid when heated with sulphuric acid. 
Potassium ferrocyanid is used to precipitate ferrocyanids from 



iron 345 

many metallic salts, giving in acid solutions of cobalt a yellowish 
green precipitate; of uranium, a brown; of copper, a chocolate; 
of barium, a yellowish white; and a white precipitate from zinc, 
nickel, tin, cadmium, lead, antimony, bismuth, silver, mercury, 
and manganese. With ferrous salts it yields white precipitates; 
passing from light blue to dark blue; with ferric salts dark blue 
ferric ferrocyanid. 

The ion Fe" is precipitated from ferrous solutions by hydrogen 
sulphid, but is not precipitated by this reagent from the solutions 
of potassium ferrocyanid, since on dissolving this salt the complex 
ferrocyanidion [Fe(CN)J //// is formed and not diferrion Fe*\ 

Ferric ferrocyanid, Fe 4 [Fe(CN) 6 ] 3 , is a highly valued pigment 
known commercially as Prussian blue. It is formed whenever 
triferrion, Fe # ", meets ferrocyanidion; and as the dark blue color 
is recognizable in very small quantities, it makes a very sensitive 
reaction for ferric salts. 

Ferricyanogen is a hypothetic group not existing free, but 
present as anion in hydroferricyanic acid, H 3 *, [Fe(CN)J /// , and 
metallic ferricyanids. The anion has the same composition as in 
ferrocyanids, but differs in being trivalent, while ferrocyanidion is 
tetravalent. Like the latter, ferricyanidion exhibits none of the 
chemical or physiologic properties of either cyanogen or iron. 

Hydroferricyanic acid, H 3 Fe(CN) 6 , can be obtained from solu- 
tions of its salts, in brown needles, by the action of strong hydro- 
chloric acid. It is tribasic. 

Potassium ferricyanid, K 3 Fe(CN) 6 (red prussiate of potash), 
is prepared from the ferrocyanid by treating it with oxidizing 
agents, such as chlorin: 

K 4 Fe(CN) 6 + CI = K 3 Fe(CN) 6 + KC1. 

Garnet red crystals separate as the solution is concentrated. 
The dry crystals are permanent, but the solution is unstable and 
must be made fresh when used as a reagent. With neutral solu- 
tions of metallic salts it yields precipitates which differ in color from 
those given by potassium ferrocyanid. The most important of 
these, showing that the solution contains diferrion, is ferrous ferri- 
cyanid, Fe 3 [Fe(CN) 6 ] 2 , a bright blue precipitate called TurnbulVs 
blue. 

Ferric sulphocyanid (Fe(SCN) 3 ) (thiocyanate) is the cause of 
the deep blood red color formed when an excess of potassium 
thiocyanate, KSCN, is added to solution of a ferric salt. The 
most pronounced reaction is obtained by having a great concen- 
tration of thiocyanate, which drives back the relatively small 
amount of triferrion into the red undissociated state. The effect 



346 THE METALS 

is enhanced by shaking with ether, which dissolves and separates 
the red undissociated ferric thiocyanate. 

Sodium nitroprussid, Na 2 Fe(CN) 5 NO . 2H 2 0, occurs in ruby- 
red crystals formed when sodium ferrocyanid is treated with nitric 
acid. It is used in Legal's test for acetone in the urine. With 
alkaline sulphids it turns purple. 

Liquor ferri acetatis is a 33-per cent, aqueous solution of 
normal ferric acetate, Fe(C 2 H 3 2 ) 3 . It is a deep red, transparent 
liquid of acetous odor and sweet ferruginous taste. It is used to 
prepare tinctura ferri acetatis, which has, in addition to the above, 
alcohol and acetic ether. 

Liquor ferri et ammonii acetatis, or Basham's mixture, is an 
agreeable preparation containing tincture of ferric chlorid, ammo- 
nium acetate, and acetic acid dissolved in a sweetened elixir of 
orange. Dose: 2 to 4 fl. dr. (8-16 c.c). 

Toxicology of Iron Salts.— Although iron is present in 
the body, also in food, and is a frequent constituent in tonic med- 
icines, yet sufficient evidence exists that at least two of its salts, 
ferrous sulphate and ferric chlorid, have toxic properties when 
taken in excessive doses. Diarrhea and abdominal pain mark the 
course of a gastro-enteritis. 

The widely used preparation tinctura ferri chloridi, or " tincture 
of iron," a brown acid liquid, is frequently mistaken for harmless 
liquids of the same color. It has been taken in toxic doses as 
an abortifacient. 

Symptoms. — When ferric chlorid has been given experimentally 
to the lower animals with food it has been found harmless even 
in considerable doses. The same amounts given fasting and in 
alcoholic solution have resulted in death in from one to sixteen 
hours. It causes an inky, metallic taste, violent abdominal pain, 
vomiting, diarrhea, paralysis of the extremities, suppression of 
urine, convulsions, and death. The feces are blackened by the 
iron sulphid formed. 

Fatal Dose. — One case has been reported of death after five 
weeks from a dose of the chlorid equal to ij oz. of the "tincture 
of iron." An ounce has caused vomiting and urinary symptoms. 
On the other hand, a man aged seventy-two recovered from the 
effects of 3 oz. of the tincture. 

Treatment. — The alkaline bicarbonates or the carbonates dis- 
solved in a large amount of water or milk may be swallowed or 
used to wash out the stomach with a pump or tube. The gastro- 
enteric symptoms should be treated by rest and anodynes. 

Postmortem Appearances. — In one case a greenish black, 
fur-like "mud" covered the tongue, esophagus, and stomach; 
swelling, congestion, and ecchymotic points were the changes noted 



MANGANESE 347 

in the liver and kidneys, and hyperemia marked the brain and its 
membranes. 

Tests. — Ammonium sulphid causes a black precipitate of iron 
sulphid with solutions of ferrous or ferric salts. It can be used after 
the metal has been extracted from the tissue with acetic acid. 
The equation for this reaction is: 

FeS0 4 + (NH 4 ) 2 S = (NH 4 ) 2 S0 4 + FeS. 

Redissolving the sulphid in nitrohydrochloric acid, the iron will 
yield to potassium jerrocyanid a blue precipitate. If the iron 
solution is almost neutralized with ammonia, then ammonium 
sulphocyanid will give a red color. 

The analytic reactions which distinguish diferrion from tri- 
ferrion may be summarized according to the following scheme, 
using ferrous sulphate for the former and ferric chlorid for the 
latter. In aqueous solution the ferrous salt is light green and 
ferric salt reddish brown. With the reagent named in the first 
column the precipitates yielded are stated in the other columns: 

Reagents. Ferrous salts. Ferric salts. 

Hydrogen sulphid. No precipitate. White precipitate of sulphur, 

and reduction to ferrous 
state. 
Ammonium sulphid. Black precipitate. Black precipitate. 

Alkalis. White precipitate, turn- Red-brown precipitate. 

ing green. 
Potassium ferrocyanid. White precipitate, turn- Prussian-blue precipitate. 

ing blue. 
Potassium ferricyanid. Dark blue precipitate. Green color, but no precipitate. 
Potassium sulphocyanid. No precipitate. Blood-red color. 

Acid tannic. No change. Greenish-black, .inky precipi- 

tate of ferric tannate. 

Detection. — Having digested the organic matters thoroughly 
in water acidulated with acetic acid, filtered, evaporated the filtrate 
to dryness, and incinerated the residue, the ash is treated with 
dilute sulphuric acid and the solution tested as above with am- 
monium sulphid and potassium ferrocyanid. Determination of 
poisonous amounts must rest upon the quantity found in the 
organs in excess of that normally present. The black fur on the 
mucous membranes and the stains on the clothing ought to yield 
significant amounts. 

MANGANESE 
Symbol, Mn. Atomic weight, 55. 

Manganese occurs in nature usually as an oxid, the most abun- 
dant being pyrolusite, Mn0 2 . The metal can be made by elec- 
trolysis of the chlorid or by reduction of the oxid by heating with 
carbon or with powdered aluminium. 



348 THE METALS 

The metal belongs to the iron group, because of its similarity 
in physical and chemical properties. When pure it is reddish 
gray in color, lustrous, and resists the action of the air fairly well, 
but the impure form rusts more easily than iron and has little 
commercial value except as an alloy of iron and bronze. 

Manganese Dioxid (Mn0 2 ) (Black Oxid of Manganese). — Of 
the seven oxygen compounds this is the only one of much impor- 
tance. It is a heavy, black crystalline mineral; its chief use in the 
arts being that of an oxidizing agent, as in the manufacture of 
chlorin from hydrochloric acid (see Chlorin, p. 118). Com- 
pressed into a cylinder with carbon it is used as the negative ele- 
ment of a Leclanche battery cell (p. 47). The energy of this cell, 
is derived largely by the loss of charges of electricity when Mn""' 
changes to ions of lower valence. 

Ions of Manganese. — In the case of the dioxid, manganese is, 
tetravalent. The series of salts of the lowest valence are called 
manganous, in which occurs the divalent ion, Mn". These differ 
from the ferrous salts in that their acid solutions do not absorb, 
oxygen from the air. Dimanganion is distinctly basic and has a 
pale reddish color. Trivalent manganese, Mn***, is weakly basic 
and occurs in the manganic compounds into which the manganous. 
pass by oxidation. The color of its unstable solutions is violet- 
red. Its salts quickly hydrolyze into brown manganic hydroxid,. 
Mn(OH) 3 . 

Manganous Sulphid (MnS).— The pink precipitate formed 
when ammonium sulphid is added to a cold solution of a man- 
ganous salt is a hydrate of manganous sulphid. On standing it 
becomes dehydrated and changes to green manganous sulphid. 
This green sulphid is precipitated immediately when the man- 
ganous solution is hot and concentrated. 

Manganous Sulphate (MnS0 4 . 4H 2 0) (Mangani Sulphas).— 
This is produced when oxygen is generated by the "wet way," 
dissolving manganese dioxid in sulphuric acid: 

Mn0 2 + H 2 S0 4 = MnS0 4 + H 2 + O. 

When purified from iron it forms pale rose-colored prisms with 
an astringent bitter taste. The crystals are soluble in water.. 
Manganous sulphate is used as a tonic adjuvant to iron. Dose: 
2 to 5 gr. (0.13-0.33 gm.). 

Hexavalent manganese is known in the salts of manganic- 
acid, H 2 Mn0 4 , which is regarded as formed from Mn(OH) 6 by 
loss of 2H 2 0. The acid itself is so unstable that it does not 
exist free, but its salts, such as potassium manganate, K 2 Mn0 4 , 
are stable in alkaline solutions. In acid or neutral solutions they 
instantly change to salts of permanganic acid. The solution of. 



MANGANESE 349 

crude potassium manganate with some potash has a green color, 
but on exposure to the air absorbs carbon dioxid, changes to 
potassium permanganate, KMn0 4 , and passes from green to 
purplish red through violet and blue. This play of colors gave 
the substance the name mineral chameleon: 

3 K 2 Mn0 4 + 2C0 2 = Mn0 2 + 2 K 2 C0 3 + 2 KMn0 4 

Potassium manganate. Potassium permanganate. 

Potassium Permanganate (KMnOJ.— This is the purple- 
red crystalline product obtained on evaporation of the red liquid 
just mentioned above. The anion here is the univalent perman- 
ganic ion (Mn0 4 )', analogous to the perchloric (C10 4 ) / . In the 
manganates the anion (MnOJ" is divalent. Permanganic acid is 
the highest stage of oxidation and may be regarded as the partial 
anhydrid of heptavalent manganese in the hydroxid Mn(OH) 7 : 

Mn(OH) 7 less 3 H 2 = HMn0 4 . 

This salt is a powerful oxidizing agent for almost all organic 
substances, and is destructive to the low organisms of infectious 
diseases. Its solutions should not be kept in contact with rubber 
or cork nor filtered through paper, or the brown manganese 
hydroxid will form. The brown stains made by it can be removed 
by oxalic or hydrochloric acid. 

"Condy's disinfecting fluid" is a 2-per cent, solution of it and 
" Darby's fluid" also contains it. 

With alkalis in the presence of reducing agents 2 molecules of 
potassium permanganate yield 3 atoms of oxygen. The decom- 
position is according to this equation, in which X is the organic 
-substance: 

2 KMn0 4 + 5H 2 + X = 2KOH + 2 Mn(OH) 4 + X0 3 . 

With acids the salt yields to reducing agents 5 oxygenations: 

2 KMn0 4 + 3 H 2 S0 4 + X=K 2 S0 4 + 2MnS0 4 + 3H 2 + X0 5 . 

It oxidizes oxalic acid to carbon dioxid and water in such exact 
proportions that its solution is used for volumetric testing of that 
substance, and conversely the oxalic acid is used to standardize 
solutions of permanganate which tend to deteriorate for a short 
length of time. 

C 2 H 2 4 + O 2C0 2 + H 2 0. 

One molecule of oxalic acid requires one atom of oxygen; there- 
fore, one liter of normal solution of oxalic acid is exactly oxidized 
by a liter of normal permanganate solution. The oxalic acid 



350 THE METALS 

decolorizes the permanganate until the acid is all oxidized; if the 
purple color persists, it shows the acid the end of the reaction. 

The oxidizing powers of this salt are brought into action when 
it is used as an antidote to the poisonous alkaloids, with which it 
reacts more promptly than with the usual gastric contents. As 
an antidote i or 2 gr. are given dissolved in 1 pt. of water, and 
then removed by the stomach-tube or emetics. When admin- 
istered in pills the excipient should be a mineral substance, such 
as kaolin and petrolatum. It decomposes alcohol and oxidizes 
glycerin and turpentine with a rapidity that is almost explosive. 
The other incompatibles are organic substances, alkaloids, acids, 
charcoal, carbolic acid, chlorids, bromids, arsenites, mercurous 
and ferrous salts, ammonia, hydrogen dioxid, sulphites and hypo- 
sulphites, and phosphites and hypophosphites. 

Tests for Manganese Salts. — With ammonium sulphid, man- 
ganous sulphate yields a flesh-colored precipitate soluble in acids. 

With ammonium or sodium hydroxid there results a white 
manganous hydroxid which oxidizes in the air to a brownish 
color and dissolves pink in oxalic acid. 

A small portion of gray manganese compound placed on plat- 
inum foil and heated with a mixture of sodium nitrate and car- 
bonate, fuses to make sodium manganate, which yields a green 
aqueous solution, changing to red on the addition of an acid. 

CHROMIUM 

Symbol, Cr. Atomic weight, 52. 

This is a white, hard, crystalline metal of difficult fusibility. 
Though readily attacked by alkalis, it resists all acids except 
hydrochloric. It forms salts of divalent dichromion, Cr", called 
chromous, and of trivalent trichromion, Cr"*, called chromic. 

The ion of chromous compounds is blue and strongly reducing 
in its effect, passing into the ion of chromic salts. 

Chromium hydroxid, Cr(OH) 3 , is a green precipitate formed 
when ammonia acts on solutions of green chromic salts. It dis- 
solves in excess of the alkali to a green liquid. One of the 
hydroxids is known as chromium green, Cr 2 0(OH) 4 , an emerald 
pigment used in the arts; it is non-poisonous. 

Chromic oxid (Cr 2 O s ) (sesqui-oxid) is green, insoluble, and 
is not easily fused or decomposed by heat. With alkaline 
hydroxids and nitrates it forms chromates in two series: one 
green, the other violet. The hydroxid formed by alkalis from the 
violet salt is violet in color. 

Chromanion. — Heated in the air with strong bases, chromium, 
compounds take up oxygen and form chromates. These are salts 



CHROMIUM 351 

of a bivalent anion (Cr0 4 ) // , which is isomorphous with sulphanion, 
(S0 4 )". This chromanion imparts its yellow color to its salts; 
such as the potassium chromates and lead chromate. 

Chromic anhydrid, Cr0 3 , with water forms true chromic acid, 
H 2 Cr0 4 . In this acid the chromium, like the manganese in man- 
ganic acid, has the valence of six, and in HCr0 5 , perchromic acid, 
a yet higher valence. A solution of potassium dichromate and 
sulphuric acid treated with a few drops of hydrogen dioxid is 
oxidized and yields the transient blue color of perchromic acid, 
which changes quickly as it evolves oxygen. But, shaken with 
ether, the blue color persists longer in the separate ethereal extract 
(p. 89). 

Potassium chromate (K 2 Cr0 4 ) (neutral chromate) is sulphur 
yellow, crystalline, and soluble. Its aqueous solution is alkaline. 
When any acid containing hydrion is added, the color changes from 
yellow to orange, and the salt that crystallizes out is the dichromate, 
xv 2 Cr 2 (J 7 . 

2 K 2 Cr0 4 + H 2 S0 4 = H 2 + K 2 S0 4 + K 2 Cr 2 7 . 

Chromanion (CrOJ" is changed to dichromanion (Cr 2 7 )" as 
indicated in this equation: 

2 (Cr0 4 )" + H- + H- = H 2 + (Cr 2 7 )". 

Potassium dichromate, K 2 Cr 2 7 , occurs in orange-red sol- 
uble crystals used by dyers and furniture stainers. Operatives 
in chemical works find that in the shape of fine aerial particles it 
irritates the respiratory passages, sets up ozena, and causes erup- 
tions and excoriations leading to chronic ulcers. 

Chromium trioxid (Cr0 3 ) (chromic acid, chromic anhydrid) is 
prepared by the action of sulphuric acid on saturated solution of 
potassium dichromate: 

K 2 Cr 2 7 + H 2 S0 4 = K 2 S0 4 + 2CrO s + H 2 0. 

It occurs in crimson prismatic needles, deliquescent, freely 
soluble, and in strong solution is acid and acts on organic matter 
with energy. This violent reaction with organic matter is the 
basis of the usual caution against using cork stoppers or mixing 
it with alcohol, ether, or glycerin. It is also incompatible with 
arsenous acid, chlorids, bromids, iodids, sulphids, oxalates, sul- 
phites, and tartrates. Its only use in medicine is external, as 
a deep caustic to the tonsils, and to papillary growths. When 
applied to fungous growths in the mouth a portion is sometimes 



352 THE METALS 

accidentally swallowed. It causes an acrid taste and burning in 
the throat, with persistent vertigo, vomiting of a ropy green fluid, 
and great prostration. In such cases chromium is found in the 
urine. Even its external use is attended with danger. One 
application of about 50 gr. in J oz. of water was made to the exter- 
nal genitals of a woman after removal of papillary vegetations. In 
twenty-seven hours she died in a state of collapse. Congestion of 
the kidneys and liver was found, and both organs contained 
chromium. 

Toxicology. — Toxic effects have resulted from potassium 
dichromate, from chromium trioxid, and from lead chromate. 
As the poisonous properties of lead chromate, chrome yellow, are 
mainly due to the lead contained in it, they are properly considered 
under the compounds of lead (p. 325). 

Symptoms. — When swallowed, the compounds of chromium 
act as gastro-intestinal irritants, with additional effects upon the 
central nervous system. They cause a disagreeable taste, vomit- 
ing, pain, diarrhea, collapse, unconsciousness, dilated pupils, very 
slow respirations, and muscular cramps. 

Fatal Dose. — Death has occurred in fourteen hours from about 
3 dr. of potassium dichromate, while, on the other hand, there has 
been a case of recovery from 273 gr. 

Fatal Period. — Death from 1 oz. has occurred in forty minutes. 

Treatment. — Chalk or magnesia should be given to neutralize 
the acid. Milk may be administered or used to wash out the 
stomach with the pump or tube. Anodynes are indicated for the 
pain, cerebral, and respiratory stimulants for the depression of the 
nervous system. 

Postmortem Appearances. — Chromic-acid preparations are 
absorbed with great rapidity both by stomach and skin, and its 
elimination is mainly by the kidneys, but to some extent by the 
liver and bowels. In acute cases death is caused by respiratory 
arrest or central nervous disturbance. In the gastro-intestinal 
tract are found inflammation, ecchymoses, and swollen follicles. 
An early morbid change is parenchymatous nephritis; the spleen 
is shrunken and the blood altered. 

Tests for Chromium Salts.— Soluble chromates yield with 
silver nitrate a red precipitate; with lead nitrate, a yellow precipi. 
tate; with boiling dilute sulphuric acid and alcohol , a green color 
and the odor of aldehyd. 

When hydrogen sulphid is added to an acid solution of a chro- 
mate, sulphur is precipitated and the red color changes to green 
from the formation of a basic chromium salt of the acid. When 
ammonium hydroxid is added to this green solution the hydroxid 
Cr(OH) 3 is precipitated as a bluish green jelly. 



zinc 353 

Ammonium sulphid causes the same green precipitate from a 
solution of any salt of chromium, such as the chlorid or sulphate. 

Detection. — Having treated organic matters with hydro- 
chloric acid and potassium chlorate, the liquid turns green from 
chromic chlorid. Ammonium hydroxid added to the filtered 
liquid in slight excess will yield hydrated chromic oxid as a pre- 
cipitate, which, after washing and drying, can be converted into 
potassium chromate by fusing with potassium nitrate and car- 
bonate. After dissolving the fused mass (which will be more or 
less yellow in color if chromium be present) in water and making 
slightly acid with acetic acid, the chromate can be detected by 
the tests given above. 

ZINC 

Symbol, Zn. Atomic weight, 65.4. 

Occurrence. — This metal occurs abundantly in nature as car- 
bonate, silicate, and sulphid (blende). Reduced by heating with 
charcoal the free metal distils into receivers from which air is 
excluded. 

Properties. — It is a white, rather soft metal, melting at 410 ° C. 
(760 F.), and at a bright-red heat volatilizing and burning. 
Commercial zinc often contains a trace of arsenic. In either 
air or water it first oxidizes and later forms a coherent coat of 
hydroxid and carbonate which protects the metal underneath. 
This coat does not dissolve in water unless the water contain 
chlorids. If heated to over 100 ° C. (212 F.) the brittle metal 
softens and can be rolled into sheet zinc which retains its tenacity 
at common temperatures. This is the form generally used in the 
arts. To protect iron sheets, tubes, and implements they are 
given a coat of zinc. Iron so treated is called galvanized iron. 
This superficial covering of zinc with its hydroxid makes the iron 
more durable. Zinc is a constituent of brass and German silver. 

The Ion of Zinc. — This metal resembles iron, manganese, and 
chromium in many respects, but, unlike those metals, it has but one 
valence. Zincion, Zn", is divalent and white, like magnesion. 
Owing to the prevalence of the metal in certain soils it is sometimes 
found in plants, and in consequence, traces are occasionally dis- 
covered in plant-fed animal tissues. Zinc has been found in the 
liver of cadavers under circumstances which precluded the pos- 
sibility of poisoning, since the clinical history presented no symp- 
toms attributable to the metal deposited. 

Zinc Oxid (ZnO) (Zinci Oxidum, Zinc White). — By burning 
the metal in the air the pigment zinc white is prepared. As com- 
pared with white lead, it is less poisonous and does not darken 
by hydrogen sulphid, but it has less covering power. 
23 



354 THE METALS 

It is a soft white powder, permanent, odorless, tasteless, and 
insoluble. Dose: i to 10 gr. (0.066-0.66 gm.). 

Unguentum zinci oxidi contains 20 per cent, zinc oxid. 

Zinc hydroxid, Zn(HO) 2 , is the white precipitate formed when 
sodium or ammonium hydroxid is added to solutions of zinc 
salts. A base added in excess redissolves the deposit. In the 
presence of much alkali, Zn (HO) 2 splits off hydrion from the 
hydroxyl: 

Zn(HO) 2 = H', H', (Zn0 2 )". 

Hydrion gives it acid properties and a soluble sodium zincate, 
Na 2 Zn0 2 , is formed: 

Zn(HO) 2 + 2NaHO = Na 2 Zn0 2 + 2H 2 0. 

In the presence of acids containing hydrion it dissociates in a 
different sense: 

Zn(HO) 2 = Zn", 2 (HO)'. 

All acids combine with the zincion to form the corresponding 
zinc salt. 

Zinc Carbonate (ZnC0 3 ) {Zinci Carbonas Prcecipitatus). — 
When solutions of zinc salts are boiled with solution of an alkaline 
carbonate a white precipitate of a basic carbonate forms, contain- 
ing hydroxid. 

Zinc phosphid (Zn 3 P 2 ) (zinci phosphidum) is a gray-black 
powder formed when phosphorus is thrown upon melted zinc. It 
is insoluble in water and alcohol. Dose: -gV to -%-§ gr. (0.0013- 
0.003 g m -)- 

Zinc Acetate (Zn(C 2 H 3 2 ) 2 , 3H 2 0).— By the action of acetic 
acid on the metal soft white scales are produced. These are 
soluble, efflorescent, metallic in taste, with an acetous odor. The 
aqueous solution, 2 gr. to 1 fl. oz., is used as a local astringent. 

Zinc in Food. — Zinc is soluble in the weak acids of foods. 
The well-known fact that milk keeps sweet longer in zinc vessels 
than in pots is explained by the neutralization of lactic acid by 
the zinc, which is taken up as a lactate. Not only may milk thus 
be contaminated, but also vinegar, soup, olive oil, and alcoholic 
liquids. The symptoms produced by articles of food thus con- 
taminated are not grave, and the effects of zinc oxid upon those 
who work in zinc factories are so inconspicuous as hardly to 
deserve the name of poisonous. The "zinc fever" sometimes 
seen in workers in brass and other foundries where zinc is vapor- 
ized and inhaled is marked by indigestion, headache, colic, diarrhea, 



zinc 355 

cramps in the legs, and peripheral neuritis, symptoms which might 
be attributable to the arsenic which is usually present in commer- 
cial zinc. Of the small amounts sometimes contained in drinking 
water stored in galvanized pipes and tanks, without doubt only 
a minute proportion is absorbed and that is soon eliminated. 
When larger doses have been taken repeatedly the metal has been 
found, in the liver and as an excretion in the bile of the gall-bladder. 
As regards toxicity, pure zinc salts are classed with those of copper 
and not with the slowly cumulative, metallic poisons, arsenic, 
antimony, mercury, and lead. 

Poisonous Salts. — Of 65 cases of acute zinc-poisoning, all 
were caused by the two soluble salts, the sulphate and the chlorid. 
The sulphate was to blame in 25 cases, of which 8 were due to 
mistaking it for " Epsom salt." Zinc chlorid was the poison in 
40 cases. The form used in 26 cases was " Burnett's Disinfec- 
tant;" in 4 it was "soldering fluid." 

Zinc Sulphate (ZnS0 4 7H 2 0) (White Vitriol).— This salt can be 
made by the action of sulphuric acid on zinc, or by heating the 
sulphid in the presence of oxygen: 

ZnS + 20 2 = ZnS0 4 . 

It is metallic in taste, freely soluble, and occurs in crystals so 
closely resembling magnesium sulphate that it is often mistaken for 
it. The zinc salt is sometimes kept in the household as a prompt 
emetic for emergencies. "Epsom salt" is also a domestic remedy, 
and both are often kept in the same closet in loose packages with- 
out labels. 

These facts account for the frequency with which accidental 
poisoning occurs. In doses of 20 or 30 gr. zinc sulphate will 
evacuate the stomach without causing much depression. This 
effect is so constant that even after doses of 1 oz. are taken re- 
covery is the rule. When complete expulsion does not occur it 
acts as a gastro-intestinal irritant, causing vomiting, purging, and, 
secondarily, dangerous prostration. In 1 case there was neither 
vomiting nor purging, but death occurred in less than four hours 
from the depressing action on the nervous system. 

Zinc chlorid, ZnCl 2 , is readily formed by dissolving zinc in 
hydrochloric acid and concentrating the solution by evaporation 
until it crystallizes. It is a very soluble, deliquescent salt, present 
in Burnett's Disinfectant, also in the embalming fluid used for 
preserving bodies for dissection. It is a dehydrating agent, con- 
densing and hardening the tissues. When zinc oxid is dissolved 
in a concentrated solution of zinc chlorid, an oxychlorid, ZnOHCl, 
crystallizes in a hard mass. A similar and less irritating oxy- 
phosphate forms when the oxid is dissolved in glacial phosphoric 



356 THE METALS 

acid. For dental purposes the plastic paste is put into cavities, 
where it rapidly hardens. It is a valuable cement. 

A soldering fluid is made extemporaneously by dissolving zinc 
to saturation in hydrochloric acid. This fluid is used to cleanse 
the surface of metals, so that the solder can make a perfect joint. 
In the shape of fused caustic sticks the chlorid is used to transfix 
cancerous tumors, the effect being to disorganize the growth for 
a considerable area, as the salt absorbs water from the tissues and 
diffuses readily. It is sometimes applied as a paste by cancer 
quacks in so careless a manner as to cause death. This external 
application to the breast may produce general symptoms of poi- 
soning by zinc, and the metal be found in the liver and other 
organs. 

Symptoms from Zinc Chlorid. — The gastro-intestinal symptoms 
are those of a powerful corrosive — a metallic taste with instant 
burning pain in mouth, throat, and stomach. The act of swal- 
lowing is difficult and painful, and the salivary flow excessive. 
Violent vomiting begins immediately, often of bloody matters; 
purging supervenes, with tenesmus and bloody stools. Collapse 
may end in coma and death in a few hours. If life be prolonged, 
nervous sequelae are common, such as perversion of the special 
senses, localized muscular spasms, muscular weakness, and aphonia. 
The local action may cause stricture of the gullet or pylorus, and 
also destruction of the glandular structure of the stomach, thus 
impairing digestion, so that inanition, extreme wasting, and even 
death may ensue. 

Fatal Dose. — The prompt emetic action of zinc sulphate has 
brought about recovery after doses of 1 oz.; death has ensued from 
taking ij oz. The caustic action of zinc chlorid has caused 
death secondarily after several weeks from the administration of 
6 gr. Recovery has been brought about after a dose of 200 gr. 

Fatal Period. — While death has occurred in about four hours, 
from administration of zinc sulphate without vomiting, and in 
another case from zinc chlorid, yet there are instances of death 
from the secondary effects of disorganization of the stomach and 
stricture of the gullet as late as one hundred and sixteen days 
after the dose. 

Treatment. — The efforts of the stomach at evacuation must be 
assisted by free drafts of warm water or warm milk. The stom- 
ach-tube may be used in the very exceptional cases when emesis 
is not prompt. The antidotes are milk, eggs, and the vegetable 
astringents containing tannin, represented by strong decoctions of 
green tea. 

Postmortem Appearances. — The usual consequences of irri- 
tant poisoning, more or less intense, are to be seen — that is, con- 



NICKEL COBALT 357 

gestion in the mouth, gullet, stomach, and intestines; areas of 
softening, ulceration, and even perforation. When death is due 
to secondary starvation, there is usually narrowing of the gullet, 
with thickening and corrugation. 

Tests for Zinc Salts. — Hydrogen Sulphid Tests. — A stream 
of this gas precipitates white zinc sulphid from an alkaline or 
neutral solution, or a solution made acid by acetic acid. This 
precipitate is soluble in the mineral acids, but insoluble in acetic 
acid, the alkalis, and the alkaline sulphids. 

Ammonium sulphid gives the same precipitate, the only white 
insoluble sulphid obtained by this procedure. 

Potassium ferrocyanid can be used to distinguish zinc sulphate 
from magnesium sulphate and oxalic acid, both of which have 
been mistaken for it. White zinc ferrocyanid is thrown down 
from a solution containing zinc sulphate, but the two others yield 
no precipitate. 

Detection. — Organic matters supposed to contain zinc may 
be digested at a gentle heat with dilute acetic acid, filtered, the 
filtrate concentrated, and the metal thrown down as sulphid by a 
stream of hydrogen sulphid. This precipitate, collected on a 
filter, is washed, dissolved in strong nitric acid, evaporated to dry- 
ness, the residue taken up with water, and precipitated as a hydra- 
tocarbonate by adding sodium carbonate and boiling thoroughly. 
Having filtered and washed the precipitate, it can be dried, ignited, 
and weighed as ZnO. A small portion of the hydrated carbonate 
may be fused on platinum with a drop of cobalt nitrate. The 
zinc is detected by the green color resulting. 

NICKEL COBALT 

Symbol, Xi. Atomic weight, 58.7. Symbol, Co. Atomic weight, 59. 

These metals belong to the iron group, their sulphids being 
soluble in acids. 

Nickel. — German silver is an alloy of nickel, zinc, and copper. 
Alloys of nickel, 25 per cent., and copper, 75 per cent., are widely 
used for coins of lower value. For this it is fitted by its hardness, 
malleability, and resistance to the action of air. Nickel-plating is 
much used to protect iron from rust. None of the salts of this 
metal are used in medicine. 

The Ion of Nickel. — In its stable compounds the element is 
present as the divalent nickelion, Ni", which imparts a green 
color to solutions containing it. 

Cobalt, like iron, melts at a high temperature, becomes coated 
with oxid in moist air, decomposes water at a red heat, and dis- 
solves in the strong mineral acids. Like iron, also, it forms two 



358 THE METALS 

series of salts, in the cobaltous occurs the divalent ion, Co"; in 
the cobaltic, the trivalent ion, Co*". The chief use of cobalt in 
the arts is to impart a dark-blue color to glass and porcelain by 
fusion with the silicates. 

Tests for Nickel and Cobalt. — Ammonium sulphid yields 
a black precipitate with salts of both metals. Ammonium hy- 
droxid causes a deposit of hydroxids, soluble in excess; that of 
nickel being green, that of cobalt blue. The hydroxids thrown 
down by potash and soda have similar colors to those caused by 
ammonium hydroxid, but are not dissolved by excess of the base. 



Vm— THE GOLD GROUP 

In this group are gold, platinum, and molybdenum, heavy 
metals whose sulphids are insoluble in water and dilute acids, but 
soluble in ammonium sulphid. 

GOLD (Aurum) 

Symbol, Au. Atomic weight, 197.25. 

As gold is found free and untarnished in nature, not combining 
with oxygen of the air at any temperature, it is classed with plati- 
num and silver as a noble metal. As a tellurid it is found in the 
combined state. 

On account of the high specific gravity of this element (19.3) 
it can be separated from earth, crushed rock, and sand by me- 
chanical washing. To separate washed gold from impurities it is 
first treated with mercury, with which it amalgamates, and then, 
on being distilled, the gold remains in the retort. 

When combined, as in the tellurid, the cyanid chemical process 
is used. The finely crushed ore is treated with potassium cyanid, 
which dissolves out the gold as a double cyanid, potassium auri- 
cyanid, KAu(CN) 4 . This salt has potassium as cation, and for 
anion a group, aurocyanidion. Metallic zinc or electrolysis can 
be used to set the gold free from the other elements. 

Properties. — Gold is a soft metal, orange yellow by reflected 
light, green by transmitted light and when molten. It melts at 
1200 C. (2192 F.) and is a good conductor of heat and elec- 
tricity. Being very malleable, it can be hammered into a thin 
translucent foil. Cohesive gold, used by dentists to fill teeth, is 
made by heating gold foil to redness, thus restoring a property 
of cohering lost when the foil was beaten out thin. It resists the 
chemical action of the strong acids singly, but is dissolved, as stated 
above, by mercury and the cyanids, and also by chlorin-water, 



PLATINUM 359 

nitromuriatic acid, alkaline hydroxids, and nitrates. To render 
it hard enough for daily use it is alloyed with silver and copper. 
Pure gold is said by the mints to be iooo fine, by jewelers 24 
carats fine; if, however, the alloy has only 75 per cent, of gold, it 
is 18-carat gold, the other 6 parts being copper and silver. 

The Ions of Gold. — The soluble salts of gold are trivalent, 
forming the ion Au", and are called auric. There are other 
compounds, known as aurous, which contain the metal as a mono- 
valent element. When an atom of gold meets the undissociated 
chlorin of chlorin-water, the electric interaction causes the former 
to be ionized to a cation and the latter to anions, while the dis- 
sociated gold chlorid dissolves. 

Au + CI + CI + CI = Au— , CI', CI', CI'. 

This is the third mode of ion formation, consisting in the simul- 
taneous charging of electricity by the contact of dissimilar atoms. 

Gold chlorid is prepared by dissolving pure gold in nitro- 
muriatic acid. From this yellow solution, by careful evaporation, 
yellow crystals are obtained of hydrochloroauric acid, HAuCl 4 . 
Stronger heat drives off HC1 and leaves soluble, deliquescent, 
brown crystals of gold trichlorid, AuCl 3 . 

Auri et sodii chloridum, NaAuCl 4 . 2H 2 0, is an orange-yellow 
soluble powder prepared from equal parts of gold chlorid and 
sodium chlorid. It is one of a large series of double salts obtained 
by the action of the solution of hydrochloroauric acid on salts, 
especially chlorids. The chlorid of gold and sodium is used in 
medicine as a tonic, and also in photography as a wash to give 
a brown-violet tone of reduced gold. Dose: 3V to yV g r - (0.002- 
0.006 gm.). 

Its toxic effects are similar to those of mercuric chlorid — i. e., 
gastro-enteritis, mental disturbances, and convulsions. The treat- 
ment is by eggs and other albuminous substances. 

Tests. — Hydrogen sulphid yields a dark brown precipitate of 
auric sulphid, Au 2 S 3 , which is insoluble in acids, but soluble in 
yellow ammonium sulphid. With ferrous sulphate sl brown pow- 
der is deposited, which when dried and burnished shows the yellow 
luster of gold. A similar reaction is obtained from other reducing 
agents, such as sulphurous acid and oxalic acids. 

PLATINUM 

Symbol, Pt. Atomic weight, 195. 

Occurrence. — This valuable element occurs in small quanti- 
ties in many places. It is found mixed with rarer and little-used 
metals of the same group called iridium, osmium, palladium, 
rhodium, and ruthenium. 



360 THE METALS 

Properties. — Platinum is gray and silvery in color, with the 
very high specific gravity 21.4. It melts with great difficulty and 
resembles gold in its indifference to the strongest reagents. It is 
used in the arts and in the laboratory for crucibles, dishes, and 
stills, resisting chemicals and high direct temperatures better than 
porcelain. It makes easily fusible alloys with molten metals, and 
is dissolved by nitrohydrochloric acid and hot alkalis. The acids 
nitric, sulphuric, hydrochloric, and hydrofluoric have no action 
upon it, but it unites with free chlorin, and, at a red heat, with 
phosphorus and sulphur. Its ductility and malleability are 
shown in the fine wire and thin sheets used in the arts. It has the 
same co-efficient of expansion as glass, and hence is used to conduct 
electricity through Edison lamps, into which it fuses without crack- 
ing the glass. 

When the double chlorid of platinum and ammonium is heated 
the platinum is set free not as white metal, but as a loose mass 
called spongy platinum. By chemical reduction of platinum 
compounds a finely divided form is obtained, known as platinum 
black. Enormous quantities of gases (several hundred volumes 
of oxygen) are absorbed by this fine powder. The reactions of the 
absorbed gases are accelerated to a pronounced degree; in this 
way platinum is a catalyzer, causing direct union of hydrogen 
and oxygen (pp. 87 and 93). 

The Ions of Platinum. — The valence of platinum is exhibited 
in two series of salts, divalent and tetravalent. 

Platinochlorids. — When dissolved in nitrohydrochloric acid 
a yellow solution is obtained, leaving on evaporation crystals of 
hydrochloroplatinic acid, H 2 PtCl 6 . This is used as a reagent for 
precipitating potassium and ammonium from solutions in the 
form of the difficultly soluble salts K 2 PtCl 6 , potassium platino- 
chlorid, and (NH 4 ) 2 PtCl 6 , ammonium platinochlorid. The cor- 
responding salt of sodium is not precipitated. These are commonly 
called double chlorids of the metals. 

Barium platinocyanid, BaPt(CN) 4 . 4H 2 0, is prepared by 
passing hydrocyanic acid into hot water containing platinous 
chlorid and barium carbonate. Like the other complex platinum 
compounds with cyanogen, it is derived from the divalent ion 
Pt(CN)/'. The light yellow crystals are iridescent, with a green- 
ish violet light. Fluorescent screens are made from it, which have 
the power of making ultraviolet rays — radium and uranium 
radiations and Rontgen rays — visible to the eye (see p. 54). 

Tests for Platinum Salts. — With hydrogen sulphid plati- 
num solutions yield a dark brown precipitate, insoluble in hydro- 
chloric acid. With potassium or ammonium hydroxid and excess 
of hydrochloric acid a yellow precipitate results. 



CERIUM — URANIUM 3 6 1 

CERIUM 

Symbol, Ce. Atomic weight, 140. 

Cerium is a rare metal of the family of alkaline earths. It 
forms two series of salts: cerous, containing tricerion, Ce"*; and 
eerie, containing tetracerion, Ce"". In the arts it is of some 
importance because its oxid, Ce0 2 , is added in small amounts to 
thoria to make the brilliant white mantles of incandescent gas 
lights. 

Cerii oxalas (Ce 2 (C 2 4 ) 3 . oH 2 0) (cerium oxalate) is a white 
powder, tasteless and odorless, insoluble in water or alcohol. 
It is used in obstinate vomiting in the form of a pill. Dose: 
1 to 5 gr. (0.06-0.66 gm.). 

THORIUM 

Symbol, Th. Atomic weight, 232.5. 

This metal is a constituent of very rare minerals, notably of 
monazite sand. Its oxid, thoria, Th0 2 , is a white powder which 
is left as a coherent mantle on firing the cotton netting of a Welsbach 
light saturated with the nitrate. An addition of about 1 per cent. 
of cerium oxid is necessary for the most perfect light. This metal 
shares with uranium and radium radio-active powers, sending out 
through opaque envelops rays which light up phosphorescent 
substances. These rays influence photograph plates and dis- 
charge electrified bodies (see p. 248). 

URANIUM 

Symbol, U. Atomic weight, 239.5. 

This metal is rare and of difficult fusibility, having no technical 
use in the pure state. It forms compounds that appear to be 
stages in a series in which it is first trivalent and last octavalent. 
Beside these it forms cations, such as U(OH) 4 " and U0 2 **, con- 
tained in the salts of uranyl. Uranium glass is a bright yellow 
with a brilliant green fluorescence. The mineral pitchblende has 
grown famous as the chief source of radium. It is a black sub- 
stance, composed mainly of uranous uranate, U(U0 4 ) 2 . 

This mineral or any salt of uranium has the power of acting 
through an opaque cover upon a photograph plate, just as if 
light had shone on it exposed. These emissions conduct away 
the charge of an electrometer, and make luminous a screen of 
barium platinocyanid. Like radium, it appears to be an inex- 
haustible source of radiant energy — chemical, electric, and optic 
(see p. 248). 



362 THE METALS 

MOLYBDENUM 

Symbol, Mo. Atomic weight, 96. 

This is a metal like uranium, with a variety of compounds and 
with a valency ranging from II. to VI. By roasting its native 
sulphid, MoS 2 , the oxid is formed. 

Molybdenum trioxid, MoO s , is the anhydrid of a series of 
acids, varying in the proportions of water. The trioxid unites 
with other acids to form more complex acids, as phosphomolybdic 
acid, H 3 P0 4 . 12M0O3, which is a reagent for precipitating alkaloids. 

Ammonium molybdate dissolved in nitric acid gives molyb- 
dic acid, H 2 Mo0 4 , which is used to precipitate phosphoric acid 
as a yellow powder, the ammonium salt of the above acid. This 
precipitate is insoluble in acids, but soluble in ammonium hy- 
droxid. From this ammoniacal solution magnesia mixture pre- 
cipitates ammonium-magnesium phosphate. 






ORGANIC CHEMISTRY 36' 



ORGANIC AND PHYSIOLOGIC CHEMISTRY 

Organic chemistry deals with the products peculiar to organ- 
ized bodies. These products are not found in nature, except 
in living organisms. The most characteristic of them have been 
made by synthesis in the laboratory, and thus it has been 
established that the same chemical forces are concerned in the pro- 
duction of both organic and inorganic substances. All of them 
are carbon compounds in which the carbon is combustible. As 
carbonates do not burn, they are considered to be inorganic. Some 
organic compounds exist in plants ready-made, like sugar, starch, 
and medicinal alkaloids; some, like urea, albumin, and oils, are 
found in animals. Many are derived from petroleum, or, like the 
anilin products and carbolic acid, are made from coal-tar; or, like 
creosote and wood spirits, result from the distillation of wood. 
Fermentations of different kinds produce alcohol and acetic acid, 
which, in turn, yield many derivatives. 

Organic analysis may be of different degrees of refinement. 
Proximate analysis may be simply the determination of water and 
solids by evaporation to dryness in a water-bath, and weighing 
the residue. The presence of carbon is detected by ignition in a 
crucible, the residue swelling up, blackening, and taking fire, 
leaving an incombustible whitish remainder. The part that burns 
is said to be organic, the remainder is stated as ash. 

A finer division is obtained from the solid residue by washing 
out the jats with ether, the extractives with hot alcohol, and the 
soluble minerals with hot water, leaving the proteins and insoluble 
minerals. The proteins may be separated into the various albu- 
mins, — the fats into saponifiable and non-saponifiable, and the 
minerals into different metallic salts. 

Ultimate analysis is performed by breaking down the com- 
pound into simpler combustion products with the heat of a Bunsen 
burner. Qualitative results are obtained by the following pro- 
cedures: 

Experiment 1. — Into a small dry test-tube put a piece of starch. 
Heat to redness while holding the tube horizontally. The starch 
swells and blackens and drops of water appear on the cool part of 
the tube. The water proves the presence of hydrogen, the charring 
proves that carbon is probably present. To make sure of the 
carbon it must be burned in a current of air and the product of 
combustion passed into lime-water. A white precipitate is char- 
acteristic of carbon dioxid. 



3 6 4 



ORGANIC CHEMISTRY 



Experiment 2. — We can detect nitrogen by causing it to com- 
bine with hydrogen as ammonia, NH 3 , which is easily identified 
by its odor and alkalinity. Into a small dry test-tube put some 
pieces of cheese, glue, quill, wool, or hair with soda-lime. A strip 
of moist red litmus-paper is held in the upper part of the tube, 
which is heated in a horizontal position. There is a disagreeable 
smell, the smoke turns the red paper blue, a dew is seen on the 
glass, and a charred residue in the bottom of the tube. 

Experiment 3. — A nitrogenous organic substance ignited with 
sodium produces sodium cyanid, NaCN. Into a small dry test- 
tube put a small quantity of uric acid. Upon it place a piece of 
sodium, twice the size, and heat in a Bunsen flame until charring 
occurs and other action ceases. While still hot the tube is stirred 
about in a test-glass of water, so that the tube breaks and its con- 
tents dissolve. The black matter may be allowed to settle or it 
may be filtered out, and the clear portion be tested for sodium 
cyanid by the Prussian-blue test. Add a few drops of fresh ferrous 




Fig. 71. — Estimation of carbon and hydrogen by combustion of organic substance: a to b, Com- 
bustion tube; e, e, asbestos plugs; / to /, copper oxid; tt, glass bulb for volatile liquid; d, platinum 
boat containing substance analyzed; I, drying tube containing calcium chlorid; m, potash bulbs; g, 
h, j, apparatus for ridding air of its moisture and carbon dioxid; k, furnace of gas burners. 



sulphate, the same quantity of ferric chlorid, and enough hydro- 
chloric acid to change the brown precipitate to a blue solution of 
ferrous ferrocyanid. 

Ultimate analysis reveals how few are the elements that enter 
into the composition of the great number of organic bodies. Of 
these few elements cyanogen contains: C and N; the hydrocar- 
bons C and H; the fats and carbohydrates have C, H, and O; 
the alkaloids C, H, O, and N; albumin has C, H, O, N, and S; 
nerve matter C, H, O, N, S, and P; hemoglobin C, H, O, N, S, 
and Fe. 

The substance to be analyzed is placed (Fig. 71) with an oxy- 
gen-yielding compound, CuO (/ to /), in*a hard glass tube (a to b) 
plugged loosely with asbestos (e, e). The tube is then heated in 
a furnace (k), while a stream of oxygen, dried in the towers of 
calcium chlorid or sulphuric acid (h, j), carries the combustion to 
the point of complete oxidation. The carbon is converted into 



ULTIMATE ANALYSIS 365 

C0 2 , which is caught in the absorption bulbs (m) containing KHO; 
the hydrogen changes to H 2 0, which is absorbed in passing through 
the tube (/) holding CaCl 2 . The increase of weight in the absorp- 
tion bulbs and drying tube stands for the carbon dioxid and water 
resulting from the combustion. The molecular weight of C0 2 is 
44, and for every 44 (11) parts, 12 (3) are carbon. The molecular 
weight of water is 18, and for. every 18 (9) parts 2 (1) are hydrogen. 
The difference between the sum of the weights and the weight of the 
body analyzed represents the oxygen which was not collected. 

Nitrogen Content. — If there be reason to believe that nitrogen 
is present, then heating in a furnace with soda-lime (Fig. 72, a to 
b and c to d) gives the N as NH 3 gas. This ammonia is caught 
by passing into HC1 contained in a suitable tube (e), where it is 
fixed as NH 4 C1. The NH 4 C1 is precipitated with platinum chlorid, 
weighed, and the calculation made on the basis of the molecular 
weight of NH 4 as 18, and nitrogen, 14. 

Example. — Let us suppose the analysis to be of a piece of 
sugar weighing 0.09005 gm. On combustion it forms 0.0539 gm. 




Fig. 72. — Nitrogen estimated as ammonia: a, Asbestos wad; a to b, soda-lime; b to c, substance 
tested and soda-lime; c to d, soda-lime; d, asbestos plug; e, absorption bulb containing hydrochloric 
acid. 

of H 2 and 0.19005 gm. of C0 2 . As i of H 2 is hydrogen, the 

sugar contains 0.0539X9- = 0.00599 gm. of H. As -3^- of C0 2 is 

carbon, the sugar contains 0.19005 xA = °-°38i9 of C. Therefore, 

100X0.00599 

100 gm. of sugar contains ■ — - =0.65 gm. of hydrogen, 

0.09005 

, 100X0.03819 ' . . 

and — - = 42.41 gm. of carbon. The remainder is oxygen. 

0.09005 

r = 42.41 

Then, to state percentage :< H= 6.65; 

I = 50.94. 

KjeldahVs process jor estimating nitrogen is a standard method 
suitable for organic solids or liquids: (1) By heating with strong 
sulphuric acid the nitrogen is converted to ammonium sulphate. 
(2) Next this acid solution is decomposed by heating with excess 
of sodium hydroxid. The ammonia gas evolves and is received 
in an absorbing fluid which is a known volume of standard acid. 
The diminution of acidity is finally determined volumetrically. 



3 66 



ORGANIC CHEMISTRY 



(i) Thus, in testing urine 5 c.c. are treated in a round-bottomed 
digesting flask of 250 c.c. capacity with a pinch of yellow mer- 
curic oxid (0.3 gm.) to assist oxidation and 20 c.c. of pure strong 
sulphuric acid. To prevent loss from spurting, a piece of paraffin 
about the size of a pea is added and the flask sloped over a small 
flame until the mixture boils. At first it blackens. In twenty 
minutes 10 gm. of ignited potassium sulphate in powder is added 
to raise the boiling-point and the gentle boiling continued for 
another forty-five minutes, by which time the black color is dis- 
charged. All the nitrogen in the urine is now dissolved as am- 
monium sulphate. 

(2) The cooled acid solution is washed into a liter flask (a) for 
decomposition and diluted to a volume of 300 c.c. Ten pieces of 
granulated zinc are added to prevent bump- 
ing and a bit of paraffin to check frothing; 
about 1 gm. of sodium thiosulphate is added 
to liberate nitrogen from mercuric oxid. 
Sodium hydroxid, 40 per cent., in excess is 
run in from the tap funnel (b), which is 
drawn out to a fine point below. On heat- 
ing, the ammonia distils into the absorp- 
tion flask (h) which contains a measured 
amount (about 30 c.c.) of one-fifth normal 
sulphuric acid. This acid has a few drops 
of methyl-orange in it and was poured into 
flask h through the absorption tube (n) so 
as to leave the broken glass in it, wet with 
the dilute acid, to catch any traces of 
ammonia which may escape the acid in 
flask (h). The ammonia enters the flask 
(h) by way of a 50-c.c. pipet which dips 
just below the surface of the acid and by 
its enlargement (d) receives any of the acid 
sucked back from flask (h) and prevents 
its entering flask (a). As soon as all the 
NaHO solution has dripped slowly in, the cock is closed and the 
mixture is boiled about a half hour, when about two-thirds have 
passed over. The methyl-orange must not change to yellow, which 
would indicate that the acid in (h) had not been sufficient. The 
evolution of ammonia being completed, the absorption tube (ri) 
is washed with water and the acid made up with water to 200 c.c. 
It is then transferred to a beaker and titrated with one-fifth normal 
sodium hydroxid in a buret. Example: Suppose it is found that 
the neutral point is reached when 20 c.c. of the equivalent soda 
solution have been added. This leaves a balance of 10 c.c. which 




Fig. 73. — Kjeldahl process, 
apparatus for decomposition of 
ammonium sulphate. 



MOLECULAR FORMULA 367 

represents the amount of acid consumed in absorbing the ammonia. 
As 1 c.c. of one-fifth normal H 2 S0 4 corresponds to 0.0028092 gm. 
of nitrogen this balance of 10 c.c. contains 0.0028092X10 = 
0.028092 of N. As 5 c.c. of urine yields this 0.028092, 100 c.c. 
would yield 20X 0.028092 = 0.561840 gm. percentage of nitrogen. 

Phosphorus and Sulphur Content. — Having removed the 
carbon and hydrogen by oxidation, the residue containing sulphur 
and phosphorus is completely oxidized by fusing a known quantity 
with a mixture of potassium nitrate and sodium carbonate. The 
P is oxidized to P 2 5 , which is determined by solution and pre- 
cipitation with magnesia mixture. The S is oxidized to S0 4 , 
which is determined by solution and precipitation with BaCl 2 . 

Empiric Formula. — When it is desired to determine the 
formula of an organic substance, we first analyze it by the com- 
bustion process and calculate the percentage of the constituents. 
The percentage divided by the atomic weight gives the propor- 
tional number of atoms, which proportion can be simplified by 
dividing each term with a common factor which in the case below 

is 3-33- 

Example. — A sample of acetic acid on combustion yielded carbon, 
39.95 per cent.; hydrogen, 6.69 per cent. Then the remainder was 
oxygen, 53.36 per cent. 

39.95 
C = = 3.33 or 1 as lowest ratio; 

6.69 
H = = 6.69 or 2 

1 y 

O = ~^ = 3-33 or 1 

Molecular Formula. — The simplest expression of the ratio 
of its elements being 1:2:1, the empiric formula of acetic acid 
would be CH 2 0. But formaldehyd, CH 2 0, acetic acid, C 2 H 4 2 , 
and lactic acid, C 3 H 6 3 , all have the same percentage composition, 
and the same empiric formula. The formula found most useful 
is one which tells the total number of atoms in the molecule. 
This molecular formula may not express the lowest ratio, but a 
multiple of it. There are several methods of deducing it, one of 
these depending on the determination of the vapor density. 

The law is that the molecular weight is equal to twice the vapor 
density (H=i) or to the specific gravity of its vapor (air=i) mul- 
tiplied by 28.88. The density of the vapor of acetic acid is 30 
times that of hydrogen; therefore, its molecular weight is 30X2 = 
60. But the formula CH 2 sums up to a molecular weight of 30; 
to make it 60 we must double the atoms and write it C 2 H 4 2 . 



368 ORGANIC CHEMISTRY 

As acetic acid is an organic acid, the analysis of one of its salts 

is of value. For this purpose the salt of silver is preferred, a 

weighed quantity of which ignited in a porcelain crucible gives 

a residue of pure silver. Experiment shows that there is but 1 

compound of silver with acetic acid, 1 atom of hydrogen being 

replaced by 1 of silver. As 100 parts of silver acetate leave a 

residue of 64.68 parts by weight of silver, the vanished portion 

was 35-32 parts of the-C, H, and O. The atomic weight of 

35.32X107.66 

silver is 107.66; therefore, - — 7-^- =58.8. In the salt 1 

04-00 

atom of hydrogen of the acid was replaced by 1 of silver and 

must be restored to get the true molecular weight: 58.8+1 = 

59.86; in round number 60. Its formula would therefore be — 

C 2 = 24 

H 4 = 4 

o 2 = 32 

60 

The cryoscopic method for determining molecular weight is 
serviceable for substances which cannot be vaporized without de- 
composition. A solution of sugar freezes at a lower temperature 
than does pure water, the depression of the freezing-point of 
weak solutions being directly proportional to the weight of sugar 
dissolved. For example, to dissolve sugar, 1 part in 100 of water, 
is to depress the freezing-point of the water from o° C. (32 F.) 
to — 0.058 ° C. (3 1.8956 ° F.); a 2-per cent, solution lowers it to 
-0.116 C. (31.7912 F.); 3 per cent., -0.174 C. (31. 6868° F.). 
On testing weak solutions of various organic substances in other 
solvents, such as acetic acid, benzene, etc., it is found that the 
lowering of the freezing-point is approximately proportional to 
the number of molecules of the dissolved substance in a given 
weight of the solvent, irrespective of the nature of the substance. 

Law of Raoult. — From these facts Raoult deduced the law 
that solutions in a given quantity of the same solvent oj the molec- 
ular weight in grams oj different substances will lower the freezing- 
point to the same degree. That is to say, with normal solutions 
(gram molecular) in a given solvent the freezing-point lowering is 
a constant quantity, called the co-efficient of molecular depression 
and indicated by K. The value of K for water is 19; for acetic 
acid, 39; for benzene, 49. 

To determine the molecular weight of an organic substance 
dissolve 1 gm. (P) in 100 of the solvent, and observe the de- 
pression of the freezing-point (D). Then, molecular weight = 

KXP 

The observation is best made with Beckmann's appa- 
ratus, described under Cryoscopy (p. 38). 



MOLECULAR FORMULA 



369 



Example. — Cane-sugar, 5.139 gm. (P), dissolved in 100 c.c. of 
water, lowered the freezing-point 0.295 ° C. (D). The constant 

19X5. 139 



for water as solvent (K) is 19; then, 



331. This is 



0.295 
very near the theoretic value, 342. 

The Boiling-point Method. — In another place it has been 
stated that dissolved substances raise the boiling-point of a solvent 
to an extent corresponding to the 
depression they cause in the 
freezing-point. In both cases 
the effect depends upon the 
ratio between the number of 
molecules of the dissolved sub- 
stance and the number of those 
of the solvent. Observations 
must first be made to fix the 
boiling-point constant of the 
solvent. This is done by noting 
the rise of boiling-point (p) of 
the solvent occasioned by dis- 
solving in 100 gm. of it, the 
molecular weight in grams of 
any non-electrolyte or undisso- 
ciated solid. The apparatus em- 
ployed is described below. 

Beckmann's Method for Deter- 
mining the Boiling-point. — The 
effect produced upon the boiling- 
point of a fluid by dissolving sub- 
stances in it is determined by the 
apparatus shown in Fig. 74. The 
solution to be studied is put in 
the glass tube, A, so as to cover 
the bulb of the thermometer. 
Below the bulb (not touching it) 
and at the bottom of this tube 

are glass beads which promote ebullition at a uniform rate. 
Rising from the boiling tube is a worm-like condenser, K, for 
returning the vapor. Surrounding the tube, A, is a double- 
walled glass jacket, B, containing some of the same solution 
that is being studied in A. Connected with B is a returning con- 
denser, K 2 . The apparatus stands on an asbestos box, heated by 
two burners below. 

First, pure water or any other solvent to be used is put in A, 
with the beads, and boiled. The special thermometer is inserted 
24 




Fig. 74. — Beckmann's boiling-point apparatus. 



370 ORGANIC CHEMISTRY 

and adjusted while in the apparatus, so that the surface of the 
mercury stands between o° C. (32 ° F.) and i°C. (33-8° F.), after 
the thermometer has been gently knocked. Heat is withdrawn 
and the tubes emptied, cleaned, and dried. Again the beads are 
put in A with a weighed amount of the pure water or other solvent. 
The thermometer is again put in place and the condenser inserted. 
The glass jacket B is also filled with the solvent, and the 
contents of A and B are both heated to boiling for twenty 
minutes. A record is made of the reading of the thermometer 
and the barometer. Again the heat is withdrawn; a weighed 
quantity of the substance, the molecular weight of which is to be 
determined, is dissolved in the solvent contained in A and B. 
The lamps are now applied and the liquids boiled, the tempera- 
ture is taken and corrected for any barometric changes. The 
record made by the pure solvent subtracted from that of the 
solution gives the rise due to the substance dissolved. The ele- 
vation is proportionate to the quantity dissolved, provided the 
substance is not volatile. 

pw 
The molecular w r eight is determined by the formula m = — , in 

rs 

which w = gram- weight of the substance dissolved; p = ihe boil- 
ing-point constant of the solvent; r = observed rise in boiling- 
point; s = gram-weight of the solvent. The value of p for water 
is 5.1; for acetic acid 25.3; for ether 21.6; for ethyl alcohol 11. 7. 

Effect of Dissociation. — The inorganic electrolytes (acids, bases, 
and salts) show greater depression of the freezing-point and ele- 
vation of the boiling-point than do the organic non-electrolytes. 
The lowering and the rise are dependent upon the number of 
particles, which in organic solutions is limited to the molecules 
dissolved. The quantities increase in value with the inorganic 
electrolytes, because their molecules are partly dissociated into 
ions which add to the number of particles in solution. 

Constitutional or Structural Formula.— Experiment with 
bases shows that only 1 of the H atoms in acetic acid, C 2 H 4 2 , is 
replaceable by a metal. To express this fact 1 atom may be set 
apart as C 2 H 3 2 H. When acted upon by phosphorus terchlorid, 
1 atom each of H and O are substituted by a single atom of 
chlorin. Then to represent this idea of the constitution, the OH 
must be set apart as in this equation: 

3 C 2 H 3 O.OH + PCI3 = 3C 2 H 3 OCl + PO3H3. 

We are justly entitled to assume that the H and O are linked 
together in the group hydroxyl. Other experiments give sanction 
to the view that 3 of the hydrogen atoms are contained in a methyl 



CLASSIFICATION OF CARBON COMPOUNDS 37 I 

group, CH 3 , and this notion, added to the others, is usually rep- 
resented in the constitutional or rational formula, CH 3 .COOH, 
which is read, methyl united with carboxyl. 

Classification of Carbon Compounds.— The starting-point 
for the study of organic chemistry is the compound consisting only 
of carbon and hydrogen, and known as a hydrocarbon. The 
other more complex substances may be regarded as derived from 
hydrocarbons by rearranging the atoms in the molecule, or by 
substituting for the hydrogen atoms other elements or groups 
of elements known as radicals. These changes are accomplished 
by the agencies referred to under Inorganic Chemistry, such as 
heat, oxidation, reduction, the energetic action of the halogens, 
nitric acid, and caustic alkalis; and by processes called organic, 
such as the fermentations and putrefactions. 

The number of substances to be grouped for study is enor- 
mous and their classification by no means easy. One which is 
not perfect, but which is generally adopted and has the merit of 
simplicity, is based upon the assumption that all organic sub- 
stances with constitutions that have been worked out are deriv- 
atives of one of two hydrocarbons, methane, CH 4 , or benzene, 
C 6 H 6 . The two great classes are (i) those closely related to 
methane, called paraffins, aliphatic or fatty compounds, and (2) 
those allied to benzene, called the coal-tar, cyclic, or aromatic 
compounds. In the paraffins the carbon atoms are linked in an 
open or arborescent chain. The aromatic compounds contain one 
or more closed chains or rings. 

I 

, 1 -A- 

-c-c- 11 1 

II — c c- 

Open chain. 



c 

I 

Closed chain. 

In both classes are found compounds, the nature of which 
is indicated in the following summary: 

(1) Hydrocarbons containing only hydrogen and carbon, as 
marsh gas, CH 4 . 

(2) Halogen derivatives, compounds in which one or more 
halogen atoms are substituted for the hydrogen of a hydrocar- 
bon, as methyl chlorid, CH 3 C1. 

(3) Alcohols, the hydroxids of hydrocarbon radicals, as ethyl 
alcohol, C,H,OH. 

(4) Aldehyds, compounds of a hydrocarbon radical and the 
group COH; for example, acetic aldehyd, CH 3 . COH. 



372 ALIPHATIC COMPOUNDS 

(5) Acids, compounds in which hydrocarbon radicals are 
united to carboxyl, COOH, as acetic acid, CH 3 . COOH. 

(6) Ethers, combinations of two hydrocarbon radicals with 
oxygen, as ethyl ether, (C 2 H 5 ) 2 or (C 2 H 5 ) . O . (C 2 H 5 ). 

(7) Compound ethers or esters, compounds formed like mineral 
salts by replacing the hydroxyl in an alcohol with an acid radical: 

C 2 H 5 OH + CH 3 C0 2 H = C 2 H 5 CH 3 C0 2 + H 2 0. 

Ethyl alcohol. Acetic acid. Acetic ether. 

(8) Ketones, compounds of two hydrocarbon radicals with car- 
bonyl, as dimethyl-ketone or acetone, CH 3 . CO . CH 3 . 

(9) Derivatives not classified in the above summary, such as: 
Carbohydrates, originally so called because they contain carbon 

joined to hydrogen and oxygen, which are combined in the same 
ratio as in water, thus: glucose is C 6 H 12 O e . They are regarded as 
being aldehyd alcohols or ketone alcohols, as when glucose is 
written CH 2 OH(CHOH) 4 COH. 

Amins and amids, compounds in which the hydrogen of am- 
monia, NH 3 , has been replaced by basic and acid radicals respec- 
tively, as ethylamin, NH 2 C 2 H 5 , and acetamid, NH 2 C 2 H a O. 

Proteins, compounds of carbon, hydrogen, oxygen, nitrogen, 
sulphur, and sometimes phosphorus or iron. They are complex 
and indefinite in structure, as albumin, fibrin, and casein. 



ALIPHATIC COMPOUNDS 

Methane (CH 4 ) (Marsh Gas).— This is the simplest member 
of a numerous series. Its common name, marsh gas, is due to 
its occurrence in the gases which bubble up on stirring the decay- 
ing vegetable matter at the bottom of stagnant pools. Another 
name, fire-damp, is given it by coal miners who encounter it 
escaping from fissures in the coal veins. It is the chief component 
of the natural gas of petroleum districts of Pennsylvania, Ohio, 
and Indiana, and of the illuminating gas manufactured by the 
distillation of bituminous coal. It is formed when steam with 
vapor of carbon bisulphid is passed over heated copper: 

CS 2 + 2 H 2 + 6Cu = CH 4 + 2Cu 2 S + 2CuO. 

This is an illustration of synthesis or building up of an organic 
compound from the elements, as CS 2 and H 2 are easily made 
from carbon, sulphur, hydrogen, and oxygen. 



METHANE 373 

Methane is prepared by heating in a hard glass tuoe i part of 
anhydrous sodium acetate with 4 parts of soda lime. 

CH 3 C0 2 Na + NaOH = CH 4 + Na 2 C0 3 

Sodium acetate. Sodium hydroxid. Sodium carbonate. 

In this reaction acetic acid is broken up, as most carbon acids 
are, by heat, yielding a hydrocarbon and a carbonate. 

Experiment. — The sodium acetate is first made anhydrous by 
heating it in a porcelain capsule until it fuses to a brown liquid. 
It must be stirred to prevent spurting. The cooled residue is 
ground with the soda-lime and introduced into a test-tube. The 
tube, fitted with a delivery tube by a cork, is held horizontally 
while being heated. The burner is kept moving to prevent melt- 
ing the glass tube. The gas is collected over water in other 
tubes. If a tubeful inverted is closed with the thumb and held 
mouth down, the gas stays in the tube and may be tested with a 
taper as hydrogen is sometimes tested. The gas burns at the 
mouth; the taper goes out as it is passed up inside the tube (PI. 1). 

Properties. — It is a colorless, odorless gas, slightly soluble in 
water, over which, however, it can be collected. It does not sup- 
port combustion, and causes suffocation when breathed. It burns 
with a non-luminous flame, and mixed in the properties of 1-5 
with air forms a highly explosive mixture. Accidents in coal 
mines are frequent from the fire-damp. Before the mixture in air 
reaches the explosive ratio the presence of the gas is detected by 
the blue flame or corpse light inside the miner's safety lamp. 



CH 4 


+ 


2 2 


= 


co 2 


+ 


2H 2 


2 volumes 


+ 


4 volumes 


= 


2 volumes 


+ 


4 volumes. 



A very marked trait is its stability, being unaffected by some 
of the most energetic chemical agents. It is equally unaffected 
and undissolved when passed through bromin in the dark, the 
caustic alkalis, strong acids, and the oxidizers, potassium per- 
manganate and chromic acid. Other hydrocarbons of the same 
class resist reagents in the same way, having feeble chemical 
energies; hence they are called paraffins — slight affinity. 

To express the constitution of methane and the valency of 
each atom in its molecule, the following diagram is used, based 
upon the tetravalence of carbon and the uni valence of hydrogen: 

H 

I 

H— C— H 

I 
H 



374 ALIPHATIC COMPOUNDS 

Ethane, C 2 H 6 , is a constituent of the natural gas of petroleum 
districts, and is dissolved in the crude petroleum. It is produced 
when methyl iodid is treated with sodium in a neutral medium: 

2CH3I + 2Na = C 2 H 6 + 2 NaI. 

Methyl iodid. Ethane. 

To show that ethane may be regarded as containing two methyl 
groups, this reaction is written — 



sg} + {£} - - ♦ £ 



This reaction illustrates a very common method of building a 
more complex compound from simpler parts. It has been shown 
how methane is formed by synthesis from its elements. Methane 
treated with a halogen, such as chlorin or iodin, forms methyl 
chlorid or iodid, which is one step toward the next highest hydro- 
carbon, ethane. The final step is to remove the halogen by its 
affinity for a metal, thus permitting the residues to unite. A 
similar process enables us to pass on to higher members of the 
same series. 

Experiment. — Fill a voltameter with a saturated solution of 
potassium acetate (CH 3 C0 2 ) / K*, containing some potassium 
hydroxid for absorption of C0 2 . The electric current causes the 
cation K to decompose water, liberating hydrogen at the negative 
pole, while at the positive pole acetanion breaks up into C0 2 , 
absorbed by the potash, and CH 3 , which combines with another 
CHo to form ethane, C 9 H R . 



D- 



CH 3 C0 2 

CH,C0 9 K ( ~ 2 " 6 



C 2 H K + 2 CO + K 2 . 



Properties. — Ethane is a colorless, tasteless gas, insoluble in 
water. It burns with a feebly luminous flame, and mixed with air 
in the right proportions is explosive. Like methane, it is very 
stable even when in contact with acids, alkalis, and oxidizers. 

The structure of ethane is indicated in the graphic formula — 

H H 

I I 
H— C— C— H 

I I 
H H 

This is deduced from the fact that univalent hydrogen cannot 
link the two carbon atoms, but carbon, being quadrivalent, can 
join the other carbon atom and leave six points for the six hydrogen 
atoms. 



BUTANE 375 

Propane, C 3 H 8 , occurs in petroleum and can be made by treating 
ethyl and methyl iodids with sodium: 

C 2 H 5 I + CH 3 I + 2 Na = C 3 H 8 + 2NaI. 

Ethyl iodid. Methyl iodid. Sodium. Propane. 

Properties. — At common temperatures propane is a gas, but 
below — 17 C. (1.4 F.) it condenses to a colorless liquid. It 
burns with a more luminous flame than either ethane or methane, 
because of the increased proportion of carbon. In its chemical 
properties it closely resembles the other two hydrocarbons. 

From the reaction given above it is concluded that propane is 

formed by the junction of the ethyl group (C 2 H 5 ) to the methyl 

(CH 3 ). Thus: 

H H H 

II . . ., I 

H— C— C— joins with — C— H 

II I 

H H H 

which would give it the constitution — 

H H H 

I I I 
H— C— C— C— H 

H H H 

This may be written CH 3 . CH 2 . CH 3 or CH 3 . C 2 H 5 . 

Butane, hexane, and a number of other hydrocarbons are found 
in petroleum, all having chemical properties similar to those of 
methane. 

Butane, C 4 H 10 . — There are two hydrocarbons of this formula. 
The one occurring in petroleum is often called normal butane. 
From its reactions it is considered to be diethyl, and may be writ- 
ten C 2 H 5 .C 2 H 5 , or CH 3 . CH 2 . CH 2 . CH 3 ; the graphic formula 
being written thus: 

H H H H 

I I I I 
H— C— C— C— C— H 

I I I I 
H H H H 

The other butane, called isobuta?ie, does not occur in petro- 
leum, and differs from the normal butane by being produced in 
different reactions and having different physical properties. All 
these hydrocarbons are alike chemically, but this is without doubt 
distinct from normal butane, though its molecular formula is the 
same, C 4 H 10 . 

A study of its methods of formation and chemical behavior 
leads to the conclusion that isobutane has the constitution CH 
(CH 3 ) 3 , or, graphically represented: 



376 



ALIPHATIC COMPOUNDS 



H H H 

I I I 
H— C— C— C— H 

I 
H 



H 



H- 



-C— H 

I 
H 



Isomerism. — The two butanes are called isomeric because 
with the same molecular formula they have different properties. 
They are said to be isomers. By reference to the graphic formulas 
given above it is plain that isomerism can be explained by a differ- 
ence in the arrangement of the atoms. When the hydrocarbons 
are represented in this way there is always found an agreement 
between the number of isomers and the number of different dia- 
grams it is possible to construct from the molecular formula, 
assuming carbon to be tetravalent and the carbon atoms to have 
the power of joining to other carbon atoms to make a skeleton or 
open chain. As the number of carbon atoms increases in the 
hydrocarbons heavier than butane, the number of possible isomers 
increases according to the law of permutation. There are three 
pentanes, nine heptanes, seventy-five decanes, etc. 

It has been shown that by similar processes of formation, start- 
ing with methane and substituting CH 3 for one atom of hydrogen, 
we could pass to ethane, from ethane to propane, from propane 
to butane, etc. Theoretically, there is no limit to the number of 
hydrocarbons that can be thus constructed, and as a matter of 
fact those up to C 40 and over are known and have been separated 
from petroleum. For these reasons it is convenient to class them 
together and arrange them in a series beginning with CH 4 , and 
following with other members according to the numbers of carbon 
atoms. The number of isomers are indicated by the figures in 
parentheses: 

SATURATED HYDROCARBONS 

PARAFFINS OR METHANE SERIES 



Methane (i) molecular weight 1 6 

Ethane (i) " " 30 

Propane (1) " " 44 

Butane (2) " " 58 

Pentane (3) " " 72 

Hexane (5) " " 86 

Heptane (9) " " 100 



. CH 



r J 
H fi \ 



• C 3 H 8 1 

C H -^ 

cm ' 

•C 6 H U | 
•C 7 H l6 ' 



2 

CH 2 

CH 2 
CH 2 
CH, 
CH. 



PARAFFINS 377 

Homologous Series. — This series is said to be homologous, 
because the members are alike in constitution and chemical 
behavior; because with increase in molecular weight there is a 
regular and gradual progression in density, boiling-point, and 
other physical properties; and because consecutive members dif- 
fer by CH 2 . The corresponding derivatives — alcohols, ethers, 
acids, etc. — may likewise be arranged in well-marked homologous 
series of similar compounds, differing consecutively by CH 2 . 

General Properties of Paraffins.— In any homologous series 
the composition of all the members can be expressed by a molec- 
ular formula in general terms. For the paraffins the general 
formula is- C„H 2n+2 , the coefficient n standing for the number of 
carbon atoms. From this general formula the molecular com- 
position of any number can be known. For example, in the 
fourth member the value of n must be 4, and 2^ + 2 = 10; thus, 
C 4 H 10 . 

There being a similarity in modes of production and chemical 
properties, it suffices to state the general properties of a series as 
illustrated in a few members. What is said about these types 
will apply with small allowances to every member of the series. 
Hence, a detailed account of each is unnecessary, and for lack of 
space will not be attempted in this work. To know the behavior 
of a few common or simple members is to have a basis for under- 
standing all the remainder. 

Nomenclature.— It will have been observed that all the names 
of the methane series terminate in ane. From and including 
the fifth member the prefix is a Greek numeral denoting the 
number of carbon atoms, as pent-ane, hex-ane, dec-sme, dodec-sme. 
On removing a hydrogen atom there is left a residue or univalent 
radical which is designated by changing the termination ane 
to yl, as meth-yl, pent-v/, etc. When the hydrogen of ethane, 
C 2 H 6 , is reduced by 2 atoms there is left a bivalent radical which 
changes ane to ene, as C 2 H 4 eth-ene; reduced by 3 atoms it leaves 
a trivalent radical, changing the final e of ene to yl, as C 2 H 3 ethen-yl. 

The derivatives of the bivalent radicals are denoted by the 
ending ylene, as eth-ylene chlorid, C 2 H 4 C1 2 (p. 381). 

Physical Properties of Paraffins.— At ordinary tempera- 
tures the first four members of this series are colorless gases; at 
lower temperatures, under pressure, they condense to liquids, with 
a readiness proportionate to the number of carbon atoms. The 
members from the fourth to the sixteenth are colorless liquids 
with boiling-points and molecular weights rising together. Above 
the sixteenth (C 16 H 34 ) the hydrocarbons are colorless solids, the 
melting-point rising as the series is ascended. They are all 
insoluble in water, but soluble in alcohol and ether. 



378 ALIPHATIC COMPOUNDS 

Chemical Properties of Paraffins.— They are all satu- 
rated compounds and therefore do not unite directly with any 
element. Their most marked trait is stability, resisting equally 
well strong acids, alkalis, and oxidizing agents. In sunlight 
chlorin and, less readily, bromin break them up, substituting 
halogen atoms for hydrogen. 

Petroleum and Natural Gas.— These are the chief sources of 
the paraffins. In western Pennsylvania and many other parts 
of the earth a gas issues from the earth under pressure, sponta- 
neously or when wells are bored to certain depths. This gas 
contains hydrogen, methane, ethane, propane, and other gaseous 
hydrocarbons. It is probably the product of the decomposition 
of remains of fish and other sea animals deposited with certain 
geologic strata. 

Another natural product of the same animal destruction in the 
rocks is petroleum or rock oil, which escapes into borings from 
cavities or gravelly strata under the pressure of gaseous con- 
stituents. 

Preparation. — Crude petroleum is a thick, yellowish or brown 
liquid, lighter than water, which is freed from extraneous organic 
matter and hydrocarbons other than paraffins by treatment with 
concentrated sulphuric acid. The acid is removed and the residue 
of oil treated with alkali. Thus purified, Pennsylvania oil is com- 
posed almost entirely of hydrocarbons of the methane series. 
This crude mixture has some of the gaseous members dissolved 
in it which make it too inflammable for use in lamps. To get the 
various gaseous, liquid, and solid components in suitable forms, it 
is necessary to separate them into mixtures of different boiling- 
points. The crude oil is distilled from large iron boilers, and the 
vapors condensed into receivers which are regularly changed as 
the temperature is made to rise from point to point. 

Fractional Distillation. — The saturated hydrocarbons are not 
decomposed by boiling, and hence may be separated and purified 
like other volatile organic substances by distilling in fractions. 
This operation is performed in the apparatus shown in Fig. 75. 
The organic mixture is placed in the flask A, which has a per- 
forated stopper carrying a thermometer, the bulb of which comes 
just below the side opening, B. This side tube connects with a 
condenser for fluids of low boiling-point, but when the tempera- 
ture must be raised above 125 ° C. (257 ° F.) the strain of hot 
vapor upon the cold tube of the condenser cracks it. In such 
cases connection is made with a single long tube, C, without an 
envelop of cold water. 

On applying heat the more volatile constituents boil first and 
are condensed into a receiver. By means of the thermometer 



PETROLEUM 



379 



the temperature can be noted and regulated. With the same 
source of heat the temperature of an organic mixture slowly and 
continuously rises, and the portions passing over at different inter- 
vals of 5 or io° or of 25 ° C. are separated by being received in 
different vessels. 

Treated on this principle petroleum yields the commercial 
products rhigolin, b.-p. 21 ° C. (69.8 ° F.); petroleum ether or 
be?izin, b.-p. 5o°-6o° C. (i2 2°-i4o° F.); gasolin or naphtha, b.-p. 



75 C. (167 F.); ligroin, b.-p. 8o°-i20° C. (i76°-248° F.); 




Fig. 75. — Apparatus for distillation: C, Condenser without water jacket for 130 C; B, condenser 
with water jacket for lower temperature. 

kerosene or astral oil for illumination, b.-p. i5o°-2 5o° C. (300 °- 
480 ° F.); paraffin oil o\' mineral oil, b.-p. 2 5o°-3oo° C. (482 °- 
572 ° F.); lubricating oil, b.-p. above 300 C. (572 ° F.). The 
residue, purified by boneblack, is the soft solid, vaselin or petrolatum, 
melting at 4o°-5o° C. (io4°-i22° F.); and at a higher melting- 
point, 5o°-75° C. (i2 2°-i67° F.), paraffin or mineral wax. Fuel 
oil is a cheap product not used for illumination, but valuable for 
heating and used for spraying marshes to kill mosquitoes. 

Flashing-point of Burning Oils. — Owing to the explosive 
mixtures made by the gases escaping from the lighter products, the 
laws prohibit the sale of burning oils which give off inflammable 



380 ALIPHATIC COMPOUNDS 

vapor at temperatures lower than the standard, usually 48 ° C. 
(120 F.). Official inspectors test the oil by the flashing test, the 
basis of which consists in the gradual heating of the oil, in which 
the bulb of a thermometer is immersed so as to determine the 
point at which a flame will cause a flash due to ignition of surface 
vapors. 

Toxicology. — Petroleum and its products are all somewhat 
poisonous, the gases by inhalation, the liquids and solids by 
swallowing. 

Symptoms. — In the oil refineries and in rubber factories using 
benzin as a solvent for rubber, inhalation causes the following 
symptoms: general debility, palpitation of the heart, staring 
eyes, hallucinations, cough, chronic bronchitis. Naphtha drunk 
is the name given to the intoxication it produces. This is some- 
times induced purposely by inhaling gasolin. In the early stage 
of this condition the victims may be excited and in high spirits. 
These symptoms are due to benzin; but the asphyxia is due to 
the deficiency of oxygen. Symptoms of intoxication have followed 
the spilling of petroleum in a tenanted room. In very severe 
cases — cardiac weakness, insensibility, and convulsions may be 
forerunners of death. When swallowed, petroleum is a local 
irritant to the stomach, causing pain, vomiting, colic, diarrhea, etc. 
After absorption it produces headache, dizziness, rapid pulse, 
labored breathing, cyanosis, drowsiness, collapse, insensibility. 
Workers in petroleum are liable to boils and a disseminated acne, 
chiefly on the arms and thighs. 

Fatal Dose. — A death is reported from J oz. of benzin; on the 
other hand, recovery has followed from taking 1 pt. of petroleum. 
Fatal cases are very rare. 

Treatment. — The stomach should be evacuated by emetics or 
by hypodermic injection of 5 drops of a 2-per cent, solution of 
apomorphin; or by the stomach-tube. Purgatives are used to 
empty the bowels. For the collapse hot applications, strychnin, 
and other cardiac stimulants. 

Postmortem appearances show no characteristic lesion. The 
odor of petroleum products should be detected in the contents gf 
the stomach and bowels. 

Detection. — The characteristic odor will be noticed in the sus- 
pected material and in the vapors obtained by fractional distilla- 
tion. The distillate will reveal the form of product by inflamma- 
bility, boiling-point, etc. 



OLEFINS 381 

UNSATURATED HYDROCARBONS 
OLEFIN SERIES 

(The possible isomerids shown by numbers in parentheses.) 

CH 2 
(1) Ethene or Ethylene, C 2 H 4 , or 

CH 2 . 

CHCH 3 
(1) Propene or Propylene, C 3 H 6 , or 







CH 2 . 


(3) Butene or Butylene, 


C 4 H 8 , or 


CHCH2CH3 
CH 2 . 


(5) Pentene or Amylene, 


C 5 H 10 , or 


CH(CH 2 ) 2 CH 3 
CH 2 . 



The action of chlorin and bromin upon the paraffins is to pro- 
duce substitution products, such as ethyl bromid and chlorid. By 
heating these with alcoholic solution of potassium hydroxid a 
new sort of hydrocarbon is formed by the loss of 2 hydrogen atoms: 

C 2 H 5 C1 + KOH = C 2 H 4 + KC1 + H 2 0. 

Ethyl chlorid. Ethene or ethylene. 

Any higher hydrocarbon of the methane series will substitute 1 
atom of hydrogen for chlorin, and then with the alkali yield the 
corresponding ethene hydrocarbon. 

The paraffin with 2 carbon atoms is ethane, C 2 H 6 , a com- 
pletely saturated compound; but ethene has 2 atoms less of hydro- 
gen, and under certain circumstances can take up this hydrogen 
again; hence it is called unsaturated. Arranged with other 
hydrocarbons formed by a similar reaction, there is made a homolo- 
gous series of the general formula, C W H 2 „. 

Nomenclature. — The termination -ene or -ylene is substituted 
for the ane of the corresponding paraffin. There is no methene 
or methylene, ethene being the simplest member. With chlorin, 
ethylene forms an oily liquid, ethylene dichlorid; hence it was 
called oil making or olefiant. From this word is derived the name 
of the series olefin. 

General Properties. — Not being saturated, the members of 
this series are unlike the paraffins, combining directly with other 
compounds or elements, and forming saturated additive products. 
The reactions of these hydrocarbons leave no room to doubt that 
their form of unsaturation is properly indicated by the relation of 

CH 2 
the carbon atoms in the structural formula for C 2 H 4 , as | 

CH 2 . 



382 ALIPHATIC COMPOUNDS 

The first four of the series are gases; the fourteen or more 
above these are liquids; the highest members are solids, showing 
an elevation in melting- and boiling-points as we pass up the 
series. Insoluble in water, they dissolve slightly in alcohol. They 
burn in air with a bright but smoky flame. Mixed in the right 
proportion with air they can be exploded. 

Ethene (ethylene, olefiant gas) occurs as a colorless constitu- 
ent of illuminating gas, to which it imparts the luminous quality 
not given by methane. 

Preparation. — Beside the mode of formation (p. 381) from 
ethyl chlorid and potassium hydroxid, ethene is prepared by 
destructive distillation of coal and many organic substances. 
Compressed in cylinders, it furnishes the gas used in the Pintsch 
system. By direct union it yields the halogen derivatives, ethyl- 
ene chlorid, C 2 H 4 C1 2 ; ethylene bromid, C 2 H 4 Br 2 ; and ethylene 
iodid, C 2 H 4 I 2 . 

Propene is methyl ethene, C 2 H 3 — CH 3 . 

Butene is dimethyl ethene, C 2 H 2 (CH 3 ) 2 ; or ethyl ethene, 
C 2 H 3 — C 2 H 5 . 

Pentene (amylene) has been produced in three isomers, only 
one of which is important. This is called pental, iso-amylene, 
or trimethyl- ethene, C 5 H 10 or C 2 H(CH 3 ) 3 . It is prepared by dehy- 
drating amylene hydrate with acids. It is a colorless inflammable 
liquid. Pental is used in medicine as an anesthetic in doses of 2 
or 3 fl. dr. (7. 50-11. 25 c.c.). 

ACETYLENE SERIES < 

C— H 
Ethine or Acetylene, C 2 H 2 , or . II! 

C — H 

C— CH 3 

Propine or Allylene, C 3 H 4 or C 2 H.CH 3 III 

C— H. 

General Properties. — They are unsaturated hydrocarbons of 
the general formula C W H 2W _ 2 , and are formed by treating the 
halogen monosubstitution products of the olefins with alcoholic 
potassium hydroxid: 

C 2 H 3 Br + KOH = C 2 H 2 + KBr + H 2 0. 

Being unsaturated, they can unite directly with 4 atoms of 
chlorin or bromin, or with 2 molecules of hydrochloric acid, 
to form additive compounds. The formula of acetylene expres- 

CH 
sive of this fact has this structure: III 

CH. 



ACETYLENE SERIES $&$ 

Up to the member C 12 H 22 they are gases or volatile liquids of 
a characteristic odor. Sparingly soluble in water, .readily in alco- 
hol, they are inflammable with a luminous but smoky flame. 

Acetylene (C 2 H 2 ) (Ethine).— The simplest of this series is 
acetylene, a constituent of coal-gas, and formed when the vapor 
of methane or coal-gas is passed through red-hot tubes. It has 
four atoms of hydrogen less than ethane C 2 H 6 . In the following 
manner it is a step in the synthesis of alcohol from its elements: 

In the presence of hydrogen the arc light between carbon 
electrodes produces it by a simple synthesis: 

Q + H 2 = C 2 H 2 . 

By nascent hydrogen it is raised to C 2 H 4 , ethylene, and this, by 
the action of sulphuric acid and water, produces ethyl alcohol, 
C 2 H 5 .OH. 

Preparation. — The most convenient method, and the one used 
industrially, is that consisting in the treatment of calcium carbid 
with water. A gaseous acetylene is evolved and calcium hydroxid 
remains: 

C 2 Ca + 2 H 2 = C 2 H 2 + CaH 2 2 . 

Experiment. — If a piece of calcium carbid is dropped into some 
water in a capsule, gas bubbles arise which take fire when touched 
with a lighted match. 

Properties. — Acetylene is a colorless gas, odorless when pure, 
but when impure has an odor resembling garlic. Readily soluble 
in alcohol, it is but feebly so in water. It liquefies under 48 
atmospheres of pressure at o° C. (32 °F.). It burns with a brilliant 
flame, and from a special jet it gives a light more intense than that 
of any other gas. Heated by a red-hot surface without air, its 3 
molecules change to the polymeric substance, benzene, C 6 H 6 , 
which accounts for the presence of benzene in coal-tar. When 
mixed with the proper proportion of air it ignites with a violent 
explosion. By cold and pressure it condenses to a very light 
liquid with a high coefficient of expansion. This is classed by 
some governments among the dangerous explosives. 

Detection. — This depends upon the fact that when passed into 
a solution of cuprous chlorid in ammonia it forms a brownish, 
amorphous copper acetylid, C 2 H 2 Cu 2 0; and the dry powder ex- 
plodes by percussion or by heat. When absorbed by water the 
acetylene solution precipitates ammoniosilver nitrate a white 
color; or ammoniocuprous chlorid, red. It is not poisonous, as 
a contaminant of the air, in amounts likely to be inhaled. 



384 ALIPHATIC COMPOUNDS 



HALOGEN DERIVATIVES OF METHANE 

The methane series cannot resist the energy of chlorin and 
bromin. Under the influence of daylight upon a mixture of 
methane and chlorin the following compounds are successively 
obtained and hydrochloric acid formed: 

Methyl chlorid CH 3 C1 S. G. 0.952 . . B. P. — 23.7 C. (—10.66° F.). 

Methylene chlorid CH 2 C1 2 " 1.377 • • " +4i-6° C. (106.88° F.). 

Chloroform CHC1 3 " 1.526 . . " 61. 2 C. (142.6 F.). 

Tetrachlormethane CC1 4 " 1.632 . . " 76.7 C. (170.06° F.). 

The reactions for the first two are indicated in the following 
equations: 



(1) CH 4 


+ 


Cl 2 


= 


CH3C1 


+ 


HC1. 


(2) CH 3 C1 


+ 


Cl 2 


= 


CH2C12 


+ 


HC1. 



To indicate that these are not additive compounds the follow- 
ing graphic equations are used: 



H H 

>< ±. 


CI 


— 


HC1 


+ 


H H 

H CI 


H |H 


CI; 


Methane. 


Chlorin. 


Methyl chlorid 



Another molecule of chlorin acting upon the methyl chlorid 
carries the change one step further. Thus: 



H H 

>< ±... 


CI 


-> 


HC1 


H H 

+ CI CI 


CI |H 


CI; 


Methyl chlorid. 




Methylene chlorid. 



Substitution. — To produce the other two derivatives requires 
the same process of extracting hydrogen and replacing it by 
chlorin, step by step. This process is called substitution. It is 
very general in the case of organic compounds; indeed, a system 
of classifying them is based upon the notion that all organic sub- 
stances can be formed from one another by substitution. This 
process differs from that of salt formation, where the hydrogen of 
an acid is replaced by a metal. All the hydrogen of the hydro- 
carbons can be substituted, but this cannot be done with the 
hydrogen of all inorganic acids, a few of which, such as phospho- 
rous and hypophosphorous acids have some hydrogen that resists 



HALOGEN DERIVATIVES OF METHANE 385 

substitution by a metal. The organic hydrogen can be replaced by 
all sorts of elements and groups, while that of acids only by metals 
or metal-like compounds. These substitution products are not 
dissociable like the mineral salts, though some organic acids, 
bases, and salts behave in the same way as the inorganic com- 
pounds. 

General Properties.— The table of chlorids shows that the 
halogen derivatives of the hydrocarbons increase in density and 
boiling-point progressively with the proportion of chlorin, bromin, 
or iodin. None of them is a salt; none of them conducts elec- 
tricity. They are sparingly soluble and their solutions do not give 
the reaction of the ions of chlorin and bromin with silver nitrate. 

Radicals. — In the above list we start with methane, CH 4 ; 
hence the substitution products are sometimes named as though 
they were species of methane. Thus CH 3 C1 is chlormethane; 
CH 2 C1 2 , dichlormethane; CHC1 3 , trichlormethane; and CC1 4 , 
tetrachlormethane. They are sometimes considered to be chlorids 
of the groups CH 3 , CH 2 , CH, and the element C. The C takes 4 
atoms of chlorin, which accords with the recognized tetravalence 
of carbon. In all these compounds this valence is evident. The 
group CH= combines with 3, and hence is trivalent; CH 2 = with 
2, divalent; and CH 3 — with 1, monovalent. These groups do not 
exist in the free state, but when combined as above hold together 
through many changes and reactions, with evidences of persistent 
identity. These methane radicals are named as follows: CH 3 , 
methyl; CH 2 , methylene; CH, methenyl. The monovalent groups, 
such as methyl, ethyl, propyl, etc., are called alkyl, or alcoholic 
radicals, and they are often indicated by the letter R. The name 
alkylene is given to the divalent radicals, such as methylene, 
ethylene, propylene, etc. Other radicals of a different order are the 
monovalent hydroxyl, —OH; carboxyl, — COOH; cyanogen, 
— CN; acetyl, — COCH 3 , and the divalent carbonyl, =CO. 

Methyl chlorid, CH 3 C1 {monochlor methane) , is a colorless gas 
of sweetish odor and taste, inflammable, burning with a greenish 
flame. Liquefied by pressure, it is applied locally for neuralgia, 
producing intense cold by its evaporation. 

Methylene bichlorid, CH 2 C1 2 {dichlormethane), an ethereal 
fluid, is an effective anesthetic, but dangerous, as it paralyzes the 
heart. 

Carbon tetrachlorid, CC1 4 (tetrachlormethane), is a colorless 
liquid having anesthetic properties. It is dangerous because of 
its effects on the heart. 

Chloroform (CHC1 3 ) (Trichlormethane). — The most important 
of the halogen derivatives of methane are the trisubstitution prod- 
ucts: chloroform, iodoform, bromoform. 



386 ALIPHATIC COMPOUNDS 

Preparation. — The method of obtaining chloroform by direct 
action of chlorin, while of great interest theoretically, is not con- 
venient nor economic. It is prepared by distilling, over a water- 
bath, ethyl alcohol or acetone with calx chlorinata, in a large flask 
fitted to a condenser. Chloroform and water distil over and 
separate by difference of density, chloroform being one and one- 
half times heavier than water. 

The reaction with alcohol is complex, that with acetone is as 
follows: 

2C 3 H 6 + 6CaOCl 2 = 2CHCl3 + 2Ca(HO) 2 +Ca(C 2 H 3 2 ) 2 + 3CaCl 2 . 

Acetone. Chloroform. Calcium acetate. 

Properties. — Chloroform is a colorless volatile liquid with a 
sweetish taste and characteristic odor. Its specific gravity is 
1. 49 1. It is neutral in reaction, sparingly soluble in water, dis- 
solving in 5 volumes of alcohol, and mixes in all proportions with 
ether, benzin, and oils. It does not flash at ordinary tempera- 
tures, but burns at very high temperatures with a green flame. It 
boils at 62 ° C. (143.6 ° F.). Mixed with a little air, in a bottle, 
and exposed to diffused daylight, it decomposes easily; to prevent 
this it is best kept in amber-colored bottles or opaque containers. 
It keeps better when 1 per cent, of alcohol is added. 

When used for inhalation near an exposed flame the same 
dangerous. irritant products of decomposition are formed as when 
kept for a long time exposed to daylight: 

CHC1 3 + O COCl 2 + HC1. 

Chloroform. Carbonyl chlorid. 

This carbonyl chlorid, or phosgene gas, may be the cause of fatal 
poisoning. 

Chloroformum venale, is the commercial article, which con- 
tains sundry hydrocarbons, free chlorin, aldehyd, and hydrochloric 
acid. These enhance the toxicity and render it unfit for inhala- 
tion. 

Chloroformum, U. S. P., is purified for inhalation and con- 
tains about 1 per cent, of alcohol. Dose, internally: 2 to 20 1TL 
(0.12-1.25 c.c); when inhaled: 1 fl. dr. (3.75 c.c), repeated. 

Tests for Impurities. — A lower specific gravity than 1.48 indi- 
cates too much alcohol. After shaking with one-half volume of 
water, separate and test the water with litmus-paper. If red, then 
hydrochloric acid is present — confirmed with silver nitrate, which 
precipitates white with chlorin and hydrochloric acid. Mix and 
shake frequently with an equal volume of pure sulphuric acid 
and set aside for one hour. If the acid separate with a brown 
color, then organic impurities are present. Shaken with potas- 
sium hydroxid, it turns brown if aldehyd be present. 



HALOGEN DERIVATIVES OF METHANE 387 

Aqua chlorojormi, U. S. P., is a saturated aqueous solution. 
Dose: 4 fl. dr. (16 c.c). 

Spiritus chlorojormi, U. S. P., is the alcoholic solution con- 
taining 6 per cent of chloroform. Dose 30 Tft (2 c.c). 

Emulsum chlorojormi, U. S. P., contains 4 per cent, of chloro- 
formi suspended in a mucilage of tragacanth and oil of almond. 

Linimentum chlorojormi, U. S. P., contains chloroform, 30 parts, 
and soap liniment, 70 parts. 

Symptoms. — The irritant action is shown by the pain in the 
throat and stomach, with or without vomiting. The symptoms 
of gastro-enteritis are soon marked. Some of the vapor is inhaled 
and the liquid itself is quickly absorbed, inducing the neurotic 
symptoms. These may be ushered in by a short period of excite- 
ment, or may begin at once with the characteristic stupor. The 
vomiting soon ceases; the breathing becomes irregular and snor- 
ing; the pulse thready; the pupils either dilated or .contracted; 
the skin clammy and livid. If the patient recover from the coma, 
the abdominal pain again becomes urgent. This is often attended 
by diarrhea and jaundice. 

Treatment. — The stomach should be emptied by the siphon 
tube or by vomiting induced with hypodermic injections of 3 to 5 
min. of a 2-per cent, solution of apomorphin hydrochlorate. For 
a draught and to wash out the stomach, the best antidote is a 
solution of a tablespoonful of sodium bicarbonate to a tumblerful 
of water. The failing heart must be stimulated with hypodermic 
injections of 2 or 3 drops of a fresh 2-per cent, solution of strychnin 
nitrate. The chest may be nicked strongly at intervals with a 
wet towel, alternating with hot applications to the chest and 
abdomen. * Electricity and artificial respiration are called for 
when the respiration is suspended. After recovery from coma 
the symptoms of gastro-enteritis must be treated as they arise. 

Fatal Dose. — By the stomach the smallest fatal dose is i fl. dr., 
given to a boy four years old. For an adult the least quantity 
swallowed that has killed is about J fl. oz. Recovery has fol- 
lowed when the dose was as much as 4 fl. oz. 

Fatal Period. — Usually death is delayed for twelve hours, 
though it has occurred within three hours. 

Toxicology when Inhaled as Vapor. — Given as an anesthetic 
in surgical practice, chloroform has caused many deaths. Sta- 
tistics warrant the estimate that 1 case out of 3000 inhalations will 
probably be fatal. It is difficult, but not impossible, to admin- 
ister chloroform to a person in very deep natural sleep. The 
odor usually arouses before a stupefying quantity has been inhaled. 
It takes between five and ten minutes in time, and between 3 and 
4 fl. dr. in i-dr. doses to produce insensibility. 



$88 ALIPHATIC COMPOUNDS 

Symptoms. — After a short period of excitement there follows 
one of lowered activity of the brain and later of the spinal cord. 
Sensation is lost early and the muscles are completely relaxed. 
Breathing is affected in the third stage and the heart's action is 
depressed. The temperature declines, the skin becomes livid, and 
if the anesthesia be prolonged, death may ensue from failure of 
respiration or cessation of the heart's activity. Some fatalities are 
traceable to the cases being obviously unfit from old age, heart 
disease, diabetes, Bright's disease, and alcoholism. It is dangerous 
to give chloroform in quantities greater than i fl. dr. or undiluted 
with air. The blood quickly absorbs it, and the centers that 
actuate and control breathing and the heart's action are paralyzed. 
Vomiting often occurs and the matter may choke the larynx. 

Fatal Dose. — This depends on the concentration. Death has 
ensued when only 15 drops were inhaled without air. It is hardly 
safe to give it in a stronger proportion than 4 parts in 100 of air. 
On the other hand, recovery has been brought about after the 
inhalation of 20 oz. properly diluted, and the administration 
distributed over twelve or more hours. 

It is dangerous to use chloroform by the open flame of a candle 
or gas burner. Its vapor is burned into the irritating and suffo- 
cative fumes of carbonyl chlorid, COCl 2 , and hydrochloric acid. 
If the operation and inhalation are prolonged, the patient, the 
physician, and nurses may all show signs of poisoning, such as 
cyanosis, difficult breathing, cough, collapse, and even death some 
hours after. 

Treatment. — When the breathing or the pulse suddenly de- 
clines there is need of artificial respiration with oxygen inhalation. 
The head should be lowered, the tongue drawn forward, and 
strychnin given hypodermically. 

Tests for Chloroform. — (1) A drop of chloroform* added to a 
mixture of 1 drop of anilin and alcoholic potassium hydroxid 
and gently warmed develops a nauseous smell of isobenzonitril: 

CHCI3 + C 6 H 5 NH 2 + 3KOH = C 6 H 5 NC + 3KCI + 3H 2 0. 

Anilin. Isobenzonitril. 

A distinctly offensive odor can be perceived when the chloro- 
form is present, 1 : 5000. 

Fallacies. — The same reaction can be obtained from iodoform, 
bromoform, chloral, and trichloracetic acid. 

(2) A reagent is made by mixing 0.3 gm. of resorcinol in 3 c.c. 
of water and 3 drops of 10 per cent, sodium hydroxid. When 
this is boiled strongly with 1 drop of chloroform it becomes yel- 
lowish red, with a beautiful greenish fluorescence. 



HALOGEN DERIVATIVES OE METHANE 



389 



(3) Having dissolved about 0.01 gm. of beta-naphthol in strong 
potassium hydroxid and warmed it, add the chloroform. A blue 
color results, changing to green and brown. 

(4) Ragsky Test. — When death is supposed to have been due 
to inhalation of chloroform, the lungs should be cut up finely and 
mixed with a small quantity of water. A flask is provided with 
a cork, perforated to admit a funnel tube passing to the bottom, and 
a short delivery tube at the top (Fig. 76). The lung mixture, made 
alkaline with sodium carbonate to fix volatile acids and free chlo- 
rin, is heated in the flask over a water-bath. The delivery tube is 
connected with a larger hard glass tube, about 18 in. long, which 
must be heated to bright redness through 4 in. of its length by 




Fig. 76. — Apparatus for detecting chloroform by the Ragsky process. 

a broad-flamed Bunsen burner. About 4 in. further along the 
tube is cooled by a condenser or by wetting a piece of muslin, 1 in. 
wide, wound about the tube. In the tube, beyond the muslin, is 
placed a moist piece of iodized starch test-paper. The end of the 
tube connects with Geissler's bulbs or a wash bottle containing 
silver nitrate solution, and the exit tube of the bottle is connected 
with an aspirator. The flask is heated, and, after the tube is red 
hot, air is drawn slowly through the whole apparatus by the aspir- 
ator. It carries air and chloroform to the hot tube, where the 
vapor decomposes into perchlorbenzene, hydrochloric acid, and 
chlorin, according to the following reaction: 



6CHCI3 = C 6 C1 C 



6HC1 



+ 



6C1. 



390 ALIPHATIC COMPOUNDS 

The perchlorbenzene is deposited as needles in the cold tube, 
the chlorin liberates iodin from potassium iodid, turning the paper 
blue, and the hydrochloric acid precipitates the silver nitrate. 

(5) Fehling's solution, when boiled, is reduced by chloroform to 
red cuprous oxid. 

Iodoform (CHI 3 ) (tri-io do methane) is closely related to chlo- 
roform, chemically. It is formed when ethyl alcohol, aldehyd, 
acetone, and some other organic substances are warmed with 
iodin and potassium hydroxid or carbonate: 

C 2 H 5 OH + 4 I 2 + 6KOH=CHI 3 + HKC0 2 + 5KI + 5H 2 0. 

Alcohol. Potassium formate. 

Experiment. — A few drops of alcohol are added to a small 
quantity of 5-per cent, solution of sodium carbonate, and the 
mixture warmed. Iodin (Lugol's solution), added gradually, 
causes the separation of iodoform. 

Properties. — It is precipitated in the above experiment as 
lustrous yellowish crystals in the form of six-sided plates having 
a disagreeable odor of saffron and an unpleasant taste of iodin. 
It melts at 119 C. (246.2 ° F.), sublimes readily, and is volatile at 
ordinary temperatures. It is insoluble in water, but soluble in 
alcohol and ether. 

Toxicology. — Iodoform is extensively used in surgical dressings 
because of its antiseptic and local anesthetic powers. Used too 
freely, it has been absorbed with poisonous results. Some of this 
action is due to iodin set free in the wounds and appearing later 
in the urine and saliva. 

Symptoms. — -In certain persons excessive use of iodoform dres- 
sings has produced local irritant effects about the wound, marked by 
redness, pain, swelling, diffused eruptions, inflamed lymphatics, 
and even death. The systemic phenomena are mainly cerebral; 
they are malaise, nausea, wakefulness, giddiness, headache, 
depression of spirits, melancholic delusions, delirium, coma, 
collapse, and death. Occasionally the type is different, the group 
of symptoms being drowsiness, stupor, and collapse. v 

Fatal Dose. — Taken internally, 30 gr. have caused death, though 
recovery has followed a dose of 120 gr. It is not regarded as 
safe to apply more than 1 dr. at a time to a wound or absorbing 
surface. 

Fatal Period. — Death may follow after several days' illness, or 
life may be prolonged for weeks. 

Treatment. — The first indication is to clear out the wound, but 
the gravest symptoms may continue, notwithstanding removal of 
the iodoform. The nervous phenomena must be treated accord- 



HALOGEN DERIVATIVES OF ETHANE 391 

ing to their nature. Hypodermic injections of normal salt solu- 
tion are of benefit. 

Postmortem Appearances. — Acute inflammation of the kidneys 
and pulmonary edema have been found, but most commonly there 
is fatty change in the kidneys, heart, and liver. 

Detection. — Mixed with an alcoholic solution of potassium 
hydroxid and kept warm for a while, iodoform yields free iodin after 
acidifying with nitric acid. The very characteristic odor may 
lead to prompt detection. If this be not perceived, the suspected 
matter is digested in water, made alkaline, and distilled. The 
distillate is again made alkaline, agitated with ether, and the 
ethereal extract evaporated, leaving six-sided lemon-yellow tablets 
and stars. 

Bromoform (CHBr 3 ) (tribr om-methane) is formed by a reaction 
like that of preparing by the action of alkali hypobromites on alco- 
hol or acetone. 

Properties. — It is a colorless, heavy liquid with a sweetish 
odor and taste, like that of chloroform. By exposure it turns 
dark from liberation of bromin. It is scarcely soluble in water, 
but soluble in alcohol and ether. 

Toxicology. — Bromoform is used in medical practice as an 
antispasmodic and sedative in the treatment of whooping-cough. 
Dose, for a child: 2 to 5 drops (0.12-0.3 c.c.) in dilute alcohol 
or emulsions. After a dose of 15 Ttl a child of four years be- 
came unconscious, with contracted pupils, labored breathing, 
and livid complexion. The child recovered after evacuation of 
the stomach and stimulation by warmth, electricity, and coffee. 



HALOGEN DERIVATIVES OF ETHANE 

Ethyl chlorid (C 2 H 5 C1) (chlorethane) is formed by the action 
of sunlight on a mixture of ethane and chlorin; or by the action 
of phosphorus pentachlorid on ethyl alcohol: 

C 2 H 5 OH + PC1 5 = C 2 H 5 C1 + POCI3 + CI. 

Ethyl alcohol. Phosphorus Phosphorus 

pentachlorid. oxy chlorid. 

Ethyl chlorid is a gas at ordinary temperature. Under pressure 
it becomes a colorless, very volatile liquid, boiling at 12.5 ° C. 
(55 F.). It is soluble in ether and alcohol, but only sparingly so 
in water. It does not precipitate silver nitrate in aqueous solution, 
as it has no chlorin ions, but when warmed with an alcoholic 
solution of silver nitrate it throws out silver chlorid. Heated with 



392 ALIPHATIC COMPOUNDS 

water or potash, under pressure, it yields ethyl alcohol. Com- 
pressed as a liquid in tubes, the vapor is expelled through a small 
opening, to play upon painful parts as a local anesthetic. It is 
highly inflammable. 

Ethyl Bromid (C 2 H 5 Br) (Bromethane, Hydrobromic Ether). 
— This compound can be formed by the same reactions as ethyl 
chlorid, substituting bromin for chlorin. It is a colorless, heavy, 
volatile liquid, with a burning taste and a pleasant smell, like that 
of chloroform. It is miscible with alcohol, ether, and chloroform. 
It behaves like ethyl chlorid with water, potash, and silver nitrate. 
Exposed to light and air it turns yellow and decomposes, as 
chloroform does, into dangerous compounds. When inhaled it 
causes rapid anesthesia with quick recovery. 

Dose, for inhalation, 2 to 3 fl. dr. (7.50-1 1.25 c.c); by the mouth, 
5 to 10 drops on sugar. It is not a safe anesthetic, as death has 
happened once in about 4000 cases. It has occurred in less than 
a minute; but, on the other hand, has been delayed for days. 
Ethyl bromid boils at 39 ° C. (102.2 ° F.), and so easily breaks 
up by the heat that isolation by distillation is extremely difficult. 
The disubstitution compound, C 2 H 4 Br 2 , ethylene bromid, has been 
given for it by mistake. This is more depressing to the heart, and 
therefore more poisonous. 

Ethyl Iodid (C 2 H 5 I) (Iodethane, Hydriodic Ether) —This is 
a clear, pleasant-smelling, neutral liquid, which rapidly turns 
brown when exposed to light and air, liberating iodin. Chemi- 
cally, it resembles the chlorid and bromid. Insoluble in water, it 
dissolves in alcohol and ether. It is given by the stomach in 
doses of 5 to 16 min. (0.3-1 c.c), as an antispasmodic. Inhaled, 
10 to 20 drops at a time, it allays bronchial irritation. It must be 
given with caution, for it depresses the heart in excessive doses. 



OXYGEN DERIVATIVES 

. • Alcohols, Ethers, Aldehyds, Acids 

ALCOHOLS 

Methyl Alcohol (CH 3 OH) (Wood Spirit, Wood Naphtha).— 
The name alcohol was formerly sacred to the spirit 0) wine, the 
volatile and stimulating essence of intoxicating beverages. Chem- 
ists having discovered that it was a compound of the radical hy- 
droxyl, HO, with a hydrocarbon radical, the name was extended to 
other compounds of like composition, classing them as the alcohols. 



alcohols 393 

To distinguish organic hydroxids the syllable u -ol" is used as 
a suffix. Thus: methanol for methyl alcohol, ethanol for ethyl 
alcohol. 

"When dry wood is heated in retorts and the distilled vapors 
are condensed, among the volatile products is found methyl alco- 
hol. By fractional distillation it is separated from the creosote 
and acetic acid that were mixed with it. It is a thin, colorless 
liquid, with a faint aromatic odor and a burning taste. Its specific 
gravity is 0.796; boiling-point 66° C. (150.8 F.); freely soluble 
in water. It burns with a non-luminous flame and without soot; it 
is used in spirit lamps for heating chafing-dishes, coffee-urns. etc. 
It dissolves shellac and other resins, and is used to make varnishes. 
For these purposes commercial forms are found in the shops, 
named Colonial spirits, Columbian spirits. 

Methylated spirit is a mixture used in the arts under the name 
"denatured alcohol," free under the excise law because the ethyl 
or common alcohol is rendered undrinkable by 10 per cent, of 
methyl alcohol with a trace of benzine. Pure methyl alcohol has 
been substituted by druggists for ethyl alcohol in preparing es- 
sences of cinnamon, ginger, peppermint, lemon, cologne, and bay 
rum. In certain States where the sale of alcoholic beverages is 
prohibited it is a common custom to drink these essences and 
cologne spirits for the ethyl alcohol they should contain when 
properly prepared. 

The physiologic action of methyl alcohol differs from that of 
ethyl alcohol in that the coma persists for longer periods. While 
in the body it is oxidized to formic acid, which is eliminated as 
sodium formate, XaC0 2 H, a stronger poison than the alcohol. 
It is formed and excreted so slowly that small repeated doses 
overlap each other with a cumulative effect. 

Symptoms. — Its exhilarating effect is quickly followed by ver- 
tigo, nausea, vomiting, headache, dilated pupils, delirium, per- 
sistent coma, and death. Or, if recovery take place, there is danger 
of more or less blindness, due to atrophy of the optic nerve. 

Fatal Dose. — Blindness has followed the taking of 5 teaspoon- 
fuls of methyl alcohol. Something less than J pt. has proved fatal. 

Fatal Period. — Death may occur in a few hours or be delayed 
two days. 

Treatment. — With the siphon tube the gastric contents should 
be diluted with warm water and the stomach emptied. Alterna- 
tions of hot and cold affusions may help the coma. Artificial res- 
piration may be called for, and the circulation need stimulation 
with strychnin. The optic neuritis will be benefited by strychnin 
and stimulants. 

Test. — Warmed with potassium bichromate and sulphuric 



394 ALIPHATIC COMPOUNDS 

acid, the methyl alcohol is oxidized to formic acid. This is sep- 
arated by neutralizing the sulphuric acid with calcium carbonate 
and precipitating the chromate with lead acetate. Filtered, the 
clear nitrate is tested for formic acid by warming it with ammonio- 
nitrate of silver. A silver mirror is formed on the glass. 

Constitution of Alcohols. — It has been stated above that 
alcohols are believed to be the hydroxids of hydrocarbon radicals. 
The proof of this structure rests upon certain reactions in which 
the alcohols behave like metallic hydroxids. On mixing hydro- 
chloric acid with methyl alcohol there is no immediate change. 
After a time, however, new chemical combinations arise in a 
manner similar to those attending the interaction of a metallic 
hydroxid and an acid. Thus: 

CH 4 + HC1 = CH3CI + H 2 0. 

Methyl alcohol. Methyl chlorid. 

This recalls the reaction of a hydroxid base and an acid forming 
a salt and water: 

KHO + HC1 = KC1 + H 2 0. 

The complete oxidation of methane by combustion is as fol- 
lows: 

CH 4 + 20 2 = C0 2 + 2H 2 0. 

Intermediate oxidation products (its alcohol, aldehyd, and acid) 
may be obtained by regulating the conditions. An alcohol is the 
first stage derived by introducing 1 atom of O into the hydro- 
carbon. Thus: 

H H 

I I 

H— C— H + O = H— C— O— H 

I I 

H H 

Methane. Methyl alcohol. 

The alcohol is no longer inert, like the hydrocarbon from which 
it was derived. The 1 atom of H linked by O to the C is peculiar. 
It is more loosely held than are the others, and easily gives place 
to other elements or groups. 

In the CH 4 of methyl alcohol there are two groups, CH 3 
methyl, and HO hydroxyl. Therefore, it may very properly be 
written CH 3 HO, the HO group stamping it as an alcohol. In 
other respects the alcohols show no basic properties, being neutral 
in reaction, non-conductors of the electric current, and undis- 
sociated into ions. Methyl chlorid lacks some of the properties of 
a salt. Its aqueous solution is a non-electrolyte, and does not 



alcohols 395 

precipitate silver nitrate. Therefore, there is no amount of dis- 
sociated chlorin, such as characterizes metallic chlorids. That 
there is an exceedingly small percentage of chloridion is shown by 
the circumstance that the mixture with silver nitrate does, after 
a long time, throw down a whitish precipitate. This infinitesimal 
amount of dissociation counts for something and, taken with other 
facts, justifies the view that alcohols are hydroxyl compounds, 
but does not warrant the name of salt for the class of which CH 3 C1 
is a representative. They are known as esters (see p. 430). 

Ethyl Alcohol (C 2 H e O or C 2 H 5 HO) {Spirits of Wine, Grain 
Alcohol, Ethyl Hydroxid). — Different varieties of ethyl alcohol are 
the result of varying degrees of dilution with water. Absolute 
alcohol is free from water, but that officially called absolute has 
only 99 per cent, of pure alcohol. Alcohol (U. S. P.) has a spe- 
cific gravity of 0.816 and contains 94.9 per cent by volume. This 
is common alcohol or rectified spirit. Alcohol dilutum (U. S. P.) 
has a specific gravity of 0.930 and contains 48.9 per cent, by vol- 
ume. It has the concentration of commercial proof spirit and is 
the form used in making some tinctures. 

Denatured alcohol, a cheap preparation of grain alcohol, 90 per 
cent., is free of internal revenue tax because it contains methyl 
alcohol 10 per cent, and benzin 0.5 per cent., which make it unfit 
for use in beverages without impairing its value to the arts. 

Preparation. — Ethyl alcohol occurs in many beverages which 
are made from starch and the sweet juices of plants by the action 
of ferments, and is prepared in three well-defined stages — malting, 
fermentation, distillation. 

Malting. — The starch of corn and other grain, of rice, and of 
potatoes is mixed with malt and water and kept for several hours 
at a temperature of about 65 ° C. (150 F.). In three hours the 
starch has changed to dextrin, maltose, and glucose. This conver- 
sion is brought about by a catalytic agent known as diastase, which 
is generated in grains of barley made into malt by the process of 
sprouting. Diastase is a soluble, unorganized, lifeless principle, 
like the pepsin of gastric juice. It is a type of the enzyms which 
hasten chemical action by their presence: 

3(C 6 H 10 O 5 ) + H 2 + diastase = C 12 H 22 O n + C 6 H 10 O 5 

Starch. Maltose. Dextrin. 

The dextrin later changes to maltose. 

2(C 6 H 10 O 5 ) + H 2 = C 12 H 22 O n . 

Fermentation. — The sweet maltose mixture, when cooled, is 
mixed with yeast, a minute plant which grows rapidly, secreting 



396 ALIPHATIC COMPOUNDS 

an enzym, zymase, which causes the decomposition of the maltose 
according to these equations: 

(1) C 12 H 22 O n + H 2 = 2(C 6 H 12 6 ) 

Maltose. Glucose. 

(2) 2(C 6 H 12 6 ) + zymase = 4C 2 H 6 + 4C0 2 . 

Glucose. Alcohol. 

Other higher alcohols are formed at the same time in small amount. 

Yeast, under the microscope, is seen to be a mass of rounded 
living cells grouped in clusters. In saccharine solutions containing 
proteid matter and phosphates these cells, called saccharomyces, 
bud, divide, and send up spore-bearing stems. This plant does 
not grow freely at temperatures below 5 C. (41 ° F.) or above 
30 C. (86° F.). Kept within these limits, the fluid gives off 
bubbles of carbon dioxid as if boiling; hence the name fermenta- 
tion (fervere = to boil). Above 30 C (86° F.) the alcoholic 
fermentation declines, but plants different from the yeast cell 
thrive, causing butyric and other decompositions. These also 
are called jer mentations, according to the definition: fermentation 
■is a transformation of an organic substance, brought about by an 
enzym produced by living cells. 

The plant called mycoderma aceti secretes an enzym which 
changes alcohol to vinegar; the plant inducing the lactic-acid 
fermentation is called the lactic ferment. 

Another form of fermentation is putrefaction, a fetid decom- 
position of dead nitrogenous organic substances induced by the 
growth of bacteria. The products of putrefaction are the foul- 
smelling gases NH 3 : H 2 S : NH 4 HS. Three conditions must be 
present to bring about any of these fermentations in their proper 
media: (1) The specific living organism secreting the ferment; 
(2) a favorable temperature, not below 5 C. (41 ° F.) nor above 
90 C. (194 F.); (3) moisture. To preserve fermentable organic 
substances unchanged one or more of these three factors must be 
eliminated: (1) germs, by killing them with antiseptics or by 
heating to 90 C. (194 F.) (above their death-point) and ex- 
cluding new spores; (2) warmth, by refrigerators; (3) moisture, 
by drying out the water, as is done for dried fruit or meat. 

Distillation. — The fermented fluid having changed to a weak 
solution of alcohol is subjected to fractional distillation. The 
first distillate contains 80 to 90 per cent, of ethyl alcohol and a 
small amount of the higher alcohols, called fusel oil. To get rid 
of the fusel oil the raw spirit is filtered through charcoal and again 
distilled, reserving the middle runnings as rectified spirit. 

Fermented Beverages. — From malted grains and flavored with 



alcohols 397 

hops are made beer, ale, and porter, containing alcohol from i to 
8 per cent. From the juice of the grape come the wines of dif- 
ferent alcoholic strength: hock, 8 per cent.; claret, 7 per cent.; 
sherry, 16 per cent.; port, 20 per cent. From cider a hard or 
fermented liquor is developed of 3 to 7 per cent, alcohol. 

Ardent spirits are liquors distilled so as to separate the alcohol 
and volatile principles from the water, non-volatile organic matter, 
and inorganic salts. Brandy (spts. vim gallici, U. S. P.) is dis- 
tilled from wine and has 50 per cent, alcohol. Whisky (spts. 
frumenti, U. S. P.) is obtained from fermented grain and has 50 
per cent, alcohol. Gin (spts. juniperi, U. S. P.) is distilled from 
malted grain flavored with juniper and contains 40 per cent. 
Rum has 45 per cent, and is distilled from fermented molasses. 
Liqueurs or cordials are alcoholic spirits made aromatic and 
sweetened. 

Properties. — Pure alcohol is a colorless, volatile liquid of an 
agreeable odor and burning taste. It quickly absorbs water from 
the air and mixes with it in all proportions. It boils at 78.5 ° C. 
(173.3 ° F.) and freezes at — 130 ° C. ( — 202° F.). It burns with 
a non-luminous flame and without soot. It is a solvent for many 
substances, gases, resins, essences, and alkaloids. It is a starting- 
point for making many medicinal and industrial chemicals. 

Toxicology. — As a poison, alcohol ranks among the most im- 
portant because of the prevalence of the habit of alcoholic excess 
and because of the diseases engendered by long-continued use. 
The cases of acute alcoholism are especially apt to follow excessive 
doses of ardent spirits, which may contain fusel oil in addition to 
the ethyl alcohol. 

Physiologic Effects. — In concentrated forms it is a local irri- 
tant to the stomach, withdrawing water from the tissues and 
coagulating albumin. When absorbed in large doses it is a cardiac, 
respiratory, and cerebral depressant. Small doses (^ fl. oz.) 
diluted are almost entirely oxidized in the body to C0 2 and H 2 0, 
supplying the place of the carbohydrates of food. Taken in 
larger amounts, 50 per cent, is eliminated, for the most part un- 
changed, by the lungs and kidneys. 

Symptoms of Acute Alcoholism. — When first seen by the phy- 
sician, the patient is in profound stupor. He is said to be dead 
drunk, and the odor of alcohol may be detected upon his breath. 
There is a history of the following symptoms: Confusion of the 
mind with flushing of the face, nervous excitement and tottering 
gait, vertigo, foolish speech, muscular weakness, ending in deep 
stupor. On recovery from the sleep, nausea, headache, and vom- 
iting are usually experienced. Though the pupils are usually 
dilated they are sometimes contracted up to the last moment. It 



398 ALIPHATIC COMPOUNDS 

is a good sign when the pupils are sensitive to light. Death from 
shock may follow in a few minutes after taking a pint of undiluted 
whisky at one time. When death is not immediate it may occur 
from coma and syncope or asphyxia. 

Fatal Dose. — Taken at one draught, a dose of ardent spirits 
containing 5 fl. oz. of absolute alcohol may prove fatal. A half- 
pint of gin has been fatal to an adult. The equivalent of 2 fl. oz. 
of absolute alcohol would probably be deadly to a child of ten 
years. 

Fatal Period. — Death has occurred in a few minutes; usually 
it comes on in ten hours, though several days may elapse before 
the final symptoms. 

Treatment. — The first indication is to wash out the stomach 
through the siphon tube, or to cause vomiting by emetics. Cold 
and hot affusions may be alternated, and warm applications main- 
tained to the extremities. Strychnin, hypodermically, may be of 
service to sustain the heart. 

Postmortem Appearances. — The odor of alcohol is perceptible 
in the internal organs. Red, congested, and inflamed areas are 
seen in the stomach lining. The lungs are usually dropsical. The 
brain and meninges may be congested and edematous, with venous 
engorgement and extravasation of blood. 

Detection of Ethyl Alcohol. — While the odor is characteristic, 
this may be due to whisky given as a remedy for the early symp- 
toms of some other condition ending in coma, such as opium- 
poisoning, uremia, diabetes, cerebral hemorrhage, or concussion 
of the brain. Being volatile, the alcohol may be separated by 
acidifying the materials with tartaric acid and distilling steam 
from another flask. The distillate is next treated with magnesium 
oxid and redistilled over the water-bath. 

Tests. — Iodoform Test. — The alcoholic liquid is mixed with a 
few drops of solution of iodin in potassium iodid, and then enough 
potassium hydroxid is added to decolorize it. On gently warming 
the mixture yellow crystals of iodoform are precipitated. The 
crystals have the odor of saffron and are hexagonal in form. The 
same reaction can be obtained from aldehyd, lactic acid, and 
acetone. 

Bichromate Test. — If an aqueous solution of alcohol be added 
to a mixture of potassium bichromate solution and sulphuric acid, 
the yellow color turns green from the chromium sulphate formed, 
and the odor of aldehyd arises, changing to that of acetic acid. 

Acetic Ether Test. — Some crystals of sodium acetate are added 
to the alcoholic solution and the mixture treated with sulphuric 
acid and warmed; the odor of acetic ether is perceived. 

Ethyl Benzoate Test. — A drop of benzoyl chlorid is shaken with 



alcohols 399 

the alcoholic liquid and warmed with sodium hydroxid to remove 
excess of the chlorid. The odor of ethyl benzoate is evolved. 

Amyl alcohol, C 5 H n HO, is the pentacarbon member of the 
alcohol series. In small amount it is a product of the yeast fer- 
mentation in the starch of corn and potatoes. In company with 
butyl alcohol it is found in an impure mixture known commonly 
as fusel oil, oil oj grain, oil of potatoes. As it has a higher boiling- 
point than ethyl alcohol, it comes over in the last stages of distil- 
lation of that spirit. A colorless oily liquid, it has a characteristic 
unpleasant odor and an acrid taste. It is insoluble in water, 
floating like an oil. In fusel oil there are two physical isomers of 
amyl alcohol, one which does not affect the plane of polarized 
light, and the other which turns it to the right and which boils 
two degrees higher. By oxidizing agents amyl alcohol is con- 
verted to valeric acid: 



C 5 H u HO + 2O = H 2 + C 5 H 10 O 



It is believed that some of the injurious effects of drinking raw 
whisky and potato spirit are attributable to the presence of this 
substance with aldehyd. Headache, giddiness, and nausea are 
among the sequels of intoxication when fusel oil is present. In 
cases of well-marked poisoning the most prominent symptoms are 
coma, lasting several hours, followed by glucose in the urine. It 
has caused dark urine from the presence of methemoglobin. 

In time changes take place in the fusel oil of raw whisky which 
deprive it of poisonous properties and improve the flavor. 

Detection of it as an impurity usually rests upon the character- 
istic odor emitted by a small quantity when allowed to evaporate 
from filter paper. 

Alcohols in General. — The term alcohol designates a large 
class of organic compounds which differ in properties and appear- 
ance, but are alike in being hydroxyl derivatives of saturated 
hydrocarbons. As the radicals differ in their valence they are 
named according to the number of hydroxyl groups they take; 
monohydric or monatomic; dihydric or diatomic; trihydric or 
triatomic. The monohydric alcohols, parallel with the methane 
series and homologous with common alcohol, and having medical 
importance, are: 









B.-P. Sp. Gr. at o c 


Methyl alcohol 


CH 3 HO 


66° C. 


(150.8° F.) 0.796. 


Ethyl 


C 2 H 5 HO 


78 C. 


(172.4 F.) 0.806. 


Propyl 


C 3 H 7 HO 


97° C. 


(206.6 F.) 0.817. 


Butyl 


C^HgHO 


117° C. 


(242.6 F.) 0.823. 


Amyl 


C 5 H„HO 


132° C. 


(289.6 F.) 0.825. 



400 ALIPHATIC COMPOUNDS 

Three alcohols can be prepared from propane, C 3 H 8 : mon- 
atomic propyl alcohol, C 3 H 7 HO; diatomic propylene alcohol, 
C 3 H 6 (HO) 2 ; and triatomic propenyl alcohol, C 3 H 5 (HO) 3 . The 
diatomic alcohols are called glycols. 

There may be alcohols with even more hydroxyl groups, tetra- 
tomic, pentatomic, etc. Mannitol is a hexatomic alcohol with six 
carbon atoms, each having a hydroxyl group attached. 

Another division is made of alcohols into primary, secondary, 
and tertiary, according as the facts warrant graphic formulas which 
show that the carbon atom combined with hydroxyl is at the 
same time directly united with i, 2, or 3 other carbon atoms. 
Thus, there are three butyl alcohols having the formula C 4 H 9 HO. 
There is good reason for employing the following graphic formulas 
to express their differences in structure: 

H 

H— C— H • H 

I I 

H— C— H H— C— H 

I I 

H— C— H H— C— H CH 3 

I I I 

H— C— H H 3 C— C— H H 3 C— C— CH 3 

I I I 

HO HO HO 

Primary butyl alcohol. Secondary butyl alcohol. Tertiary butyl alcohol. 

(C 3 H 7 . CH 2 OH) (C 2 H 5 . CH 3 . CHOH) (CH 3 . CH 3 . CH 3 . COH.) 

A primary alcohol is one in which the carbon atom in union 
with the hydroxyl is directly united with only 1 other carbon atom; 
a secondary alcohol is one in which the carbon atom in union 
with the hydroxyl is directly united with 2 other carbon atoms; 
a tertiary alcohol is one in which the carbon atom in union with the 
hydroxyl is directly united with 3 other carbon atoms. There is 
a decided difference among these three alcohols, especially in their 
behavior under the action of oxidizing agents. Thus: 

Primary, alcohols are converted first into aldehyds, next into 
acids containing the same number of carbon atoms, and on further 
oxidation break up (pp. 406 and 417). 

Secondary alcohols are converted into acetones, which upon 
further oxidation break up into acids with a smaller number of 
carbon atoms (p. 412). 

Tertiary alcohols are decomposed without previous formation 
of aldehyds or acetones, yielding acids with a smaller number of 
carbon atoms. 



ALCOHOLS 40I 

DIHYDRIC ALCOHOLS OR GLYCOLS 

The members of this group are called glycols, after the name 
of the simplest one, C 2 H 4 (OH) 2 , ethylene glycol, which corresponds 
with ethyl alcohol. 

Ethylene Glycol.— When ethylene bromid, C 2 H 4 Br 2 , is heated 
with a dilute alkali the bromin is replaced by hydroxyl, and eth- 
ylene alcohol is obtained. Its structure is indicated by this 
equation: 

CH 2 Br CH 2 OH 

I + 2KOH = J + 2 KBr. 

CH 2 Br CH 2 OH 

Properties. — Ethylene glycol is a thick colorless liquid with a 
sweetish taste, freely soluble in water and alcohol. It is a type 
of the class, all being neutral oily liquids, prepared by boiling the 
dibromo-additive products of the olefins with alkalis. In compo- 
sition they have two hydroxyl groups, thus differing from mono- 
hydric alcohols as calcium hydroxid, Ca(OH) 2 , differs from potas- 
sium hydroxid, KOH. With monobasic acids they form two 
esters, neutral and alcoholic. Thus, mono-acetic glycol has one 
alcoholic group left in it, CH 2 (C 2 H 3 2 ). CH 2 OH, while diacetic 
glycol has all the hydroxyl replaced by the acid, CH 2 (C 2 H 3 2 ). 
CH 2 (C 2 H 3 2 ). 

Under the action of oxidizing agents one alcoholic group 
changes to COOH, characteristic of acids, and an oxyacid is 
formed. If both alcoholic groups are oxidized a diacid is the 
product. Thus: 

CH 2 OH COOH COOH 

i I I 

CH 2 OH CH 2 OH COOH 

Glycol. Oxyacetic acid. Oxalic acid. 

TRIHYDRIC ALCOHOLS 

On a preceding page it has been stated that the paraffin pro- 
pane, by substitution of hydroxyl groups successively, can be 
converted, first, into monohydric propyl alcohol, C 3 H 7 OH; next, 
into dihydric propylene alcohol, C 3 H 6 (OH) 2 ; and, last, to tri- 
hydric propenyl alcohol, C 3 H 5 (OH) 3 . This last named is the only 
trihydric alcohol prepared with ease and which has been well 
studied. It is used in medicine under the common name of 
glycerin. The three groups containing hydroxyl are represented 
in the formula: CH 2 OH, CHOH, CH 2 OH. The trihydric class 
corresponds to the metallic bases, like bismuth hydroxid, Bi(OH) 3 . 

Glycerinum, U. S.^P., Glycerol (C 3 H 5 (OH) 3 ) (Glycerin, Pro- 
penyl Alcohol, or Glyceryl Alcohol). — This is obtained by the action 
of superheated steam, by fermentation, or by saponification upon 



402 ALIPHATIC COMPOUNDS 

fats which are not very stable compounds of weak fatty acids with 
glycerol, which is weakly basic. 

C 3 H 5 (O.C 18 H 35 0) 3 + 3 H 2 = C 3 H 5 (OH) 3 + 3 (C 18 H 35 O.OH) 

Tristearin. Glycerin. Stearic acid. 

After separation of the pasty mass of stearic acid the aqueous 
distillate is decolorized by charcoal and concentrated by evapora- 
tion. Redistillation is used to free it from the water which is 
collected in the first fractions condensed. 

Properties. — Pure anhydrous glycerin is a colorless crystal, but 
as commonly prepared contains some water, and is then an odor- 
less thick liquid with a specific gravity of 1.265 at I 5° C. (6°° F.). 
It is very hygroscopic, absorbing water from the air, and is freely 
miscible with water and alcohol, but not with ether and chloroform. 
It is a solvent for many solids and liquids, the official solutions 
being called glycerites, as the glycerite of carbolic acid. The 
taste is sweet, a property common to the glycols and other alcohols 
containing many hydroxyl groups, such as mannitol and dulcitol. 
Glycerin is an antiputrescent and antiseptic, but undergoes decom- 
position into acrolein and water under the action of heat and 
various chemicals. 

Tests. — Acrolein Test. — Heated with sulphuric acid it splits off 
2 molecules of water, leaving acrolein, a colorless liquid, giving 
an irritating vapor with an unpleasant odor like burning grease: 

C 3 H 5 (OH) 3 = C 3 H 4 + 2 H,0. 

Glycerol. Acrolein. 

F Chung's Test. — Adulterations with glucose are detected by 
Fehling's test (see p. 602). Pure glycerin does not respond to 
this test nor will it ferment with yeast. 

Borax Test. — Having fused borax in a platinum loop the bead 
is wet with glycerin and again heated. A green color to the 
flame shows that boric acid has formed a volatile ester with the 
glycerin. 

ETHERS (Simple and Mixed) 

In another place reasons were given for regarding alcohols as 
hydroxids of hydrocarbon radicals. If hydroxyl be considered as 
derived from water by the loss of 1 atom of hydrogen, then alco- 
hols, as hydroxids, may be constructed on the water plan by 
replacing that atom of hydrogen with the radical. Thus, water 

H C H 

being tt>0, ethyl alcohol is ^ 5 >0. 

By substituting another ethyl group for the remaining atom of 

C* FT 

hydrogen in hydroxyl, we get an oxid. Thus, p 2 „ 5 >0 (p. 372). 



ETHERS 



403 



This oxid, (C 2 H 5 ) 2 0, is a substance long known as ether. Other 
monovalent radicals can be linked by oxygen in the same way, 
and thus give rise to a class of oxids or ethers named after the 
radicals contained in them. In the series of simple ethers, (CH 3 ) 2 0, 
is methyl ether; (C 2 H 5 ) 2 is ethyl ether, the ordinary form. By 
manipulation at the right moment the 2 hydrogen atoms may 
be replaced by two different radicals, making a mixed ether, 

PH 

such as p t| >0, methylethyl ether. 

The ethers bear the same relationship to the metallic oxids 
that the alcohols do to the metallic hydroxids: 

C 2 H 5 . OH corresponds to K . OH. 

C 2 H 5 . O . C 2 H 5 " K . O . K. 

As ether contains no HO group it is unaffected by potassium and 
does not form esters with weak acids like those made by alcohol. 




Fig. 



-Apparatus for making and distilling ether. 



Ethyl ether (C 4 H 10 O) {(Ether, sulphuric ether, ethyl oxid) 
is prepared by a continuous process of distilling alcohol with con- 
centrated sulphuric acid. A flask having a thermometer and a 
delivery tube connected with a condenser (Fig. 77) is fitted with 



404 ALIPHATIC COMPOUNDS 

a funnel having a stop-cock. The funnel is charged with 90-per 
cent, alcohol and the tap closed. Five parts of alcohol and 9 
parts of sulphuric acid are heated in the flask to the boiling-point, 
140 C. (284 F.). This temperature is maintained, for it is the 
point at which ether distils over, and at which alcohol remains in 
the flask. From the funnel fresh alcohol is slowly supplied to 
take the place of the ether which collects in the receiver. In the 
flask there accumulates water to dilute the sulphuric acid, which 
ultimately becomes too weak to act. Up to that limit the same 
small quantity of acid serves to convert a large quantity of alcohol 
to ether. On comparing the molecular formula of ether, C 4 H 10 O, 
with a proportional formula (2 molecules) of alcohol, 2C 2 H 6 or 
C 4 H 12 2 , it is seen that 

C 4 H 10 O = C 4 H 12 2 minus H 2 0; 

that is, ether is the anhydrid of alcohol, the elements of water 
being abstracted by sulphuric acid. The process has two stages, 
as shown in the equations: 

C2 H 5 >° + H> SO < " C H 5>SO < + H *°- 

Alcohol. Sulphuric acid. Ethyl hydrogen sulphate. 

Q h 5 >so 4 + c |f 5 >o = cjt>° + H * so <- 

If a mixture of two alcohols be used, the distilled product will 
consist of three ethers. Thus, methyl and ethyl alcohols yield 
methyl ether, ethyl ether, and the mixed methylethyl ether, 
CH 3 . O . C 2 H 5 . 

Properties. — Ether is a colorless, neutral, mobile liquid with a 
characteristic sweetish smell. Its specific gravity is 0.736; its 
boiling-point 35 ° C. (95 ° F.). The official ether (aether, U. S. P.) 
contains 4 per cent, of alcohol, which raises the boiling-point. 
Ether is highly volatile and inflammable. Exposed to the air, an 
explosive mixture of its vapor and air at once forms, which renders 
experimentation with it dangerous and its administration near an 
open flame unsafe. When this exposure is unavoidable, the light 
should be well above the ether, as its vapor, being heavier than the 
air, settles down. 

C 4 H 10 O + 60 2 = 4 C0 2 + 5 H 2 0. 

Ether. Air. 

Experiment. — Into a slightly warmed beaker put 2 c.c. of 
ether and cover it until the ether has filled the beaker with vapor. 



4 ETHERS 405 

Pour the heavy vapor into an empty beaker and prove its presence 
by a lighted taper. \ 

Miscible in all proportions with alcohol, chloroform, and other 
organic liquids, ether requires 10 volumes of water to dissolve it. 
In the arts it is used as a solvent for oils, resins, alkaloids, v bromin, 
and iodin. In surgery it is used enormously as an anesthetic, 
the physiologic effects being those of alcohol, but the narcotism 
comes on more promptly and is more transient. When sprayed on 
the skin its rapid evaporation lowers the temperature and causes a 
local numbness. Spiritus cztheris, U. S. P., contains 1 part of ether 
with a little more than 2 parts of alcohol. Dose: 1 fl. dr. (4 c.c). 
Spiritus cetheris compositus (Hoffman's anodyne) is a mixture of 1 
part of ether and 2 parts of alcohol with 2.5 per cent, of ethereal 
oil. Dose: 5 to 60 TTL (0.33-4 c.c). 

Toxicology. — As an anesthetic, ether is safer than chloroform, 
the record justifying expectation of 1 death in 12,000 etherizations. 
It is sometimes used for suicidal purposes and as a habitual 
intoxicant. 

Symptoms. — When inhaled, the vapors irritate the larynx and 
increase the flow of saliva and mucus. Unconsciousness comes 
on soon, the pulse and breathing becoming slow and irregular. 
An overdose may cause death by asphyxia. Notably dangerous 
is the sequel, in the shape of pneumonia from pulmonary irrita- 
tion. When taken by the stomach, ether causes a sense of local 
irritation in stomach and bowels, and symptoms of general intoxi- 
cation come on quickly. 

Fatal Dose. — By inhalation death has followed 2\ fl. oz. (75 
c.c). Continuous inhalation of air containing 6 per cent, of ether 
vapor arrested respiration in ten minutes. Anesthesia may be 
induced with about half that concentration in the same period of 
time. 

Fatal Period. — Failure of respiration may occur before or 
after full unconsciousness. The pulmonary and renal sequels 
may cause death days after recovery from the narcotism. 

Treatment. — The immediate indication is for fresh air and res- 
piratory stimulants, such as ammonia, artificial respiration, oxygen, 
and hypodermic doses of strychnin. 

Detection. — If not identified by odor or information from the 
surroundings, the detection is most difficult, as the ether quickly 
escapes from the body by its vaporization. A few drops may be 
recovered by distillation at a low heat and condensation in re- 
ceivers surrounded by a mixture of salt and ice. The distillate 
will have the ethereal odor, will burn quickly, evaporate, and its 
vapor will turn to green the yellow spot made on filter paper with 
potassium bichromate and sulphuric acid. 



406 ALIPHATIC COMPOUNDS 

ALDEHYDS 

These compounds are the first stage in the process of oxida- 
tion of alcohols, the next products being the acids. As the first 
effect of oxidizing an alcohol is the abstraction of 2 atoms of 
hydrogen to form water, the resulting compound was named by 
blending significant syllables from the phrase "a/cohol dehydroge- 
natum." 

CH 4 + O CH 2 + H 2 0. 

Methyl alcohol. Formaldehyd. 

C 2 H e O + O C 2 H 4 + H 2 0. 

Ethyl alcohol. Acetaldehyd. 

The structural changes are represented by graphic equations 
thus: 

H H 

(i) H — C — O-j-H + O = H — C = -f H a O. 

j 1" ' 

; H 

Methyl alcohol. Formaldehyd. 

H O.H 

(ii) H-CzO -f- O = H — C = 0. 

Formaldehyd. Formic acid. 

Structure. — With phosphorus pentachlorid the aldehyds yield 
phosphoric oxychlorid and ethyledene chlorid, thus: 

C 2 H 4 + PC1 5 = POCI3 + C 2 H 4 C1 2 . 

Ethyl aldehyd. 

The atom of oxygen alone is replaced by 2 of chlorin, which 
would not happen if the oxygen were in a hydroxyl group, but is 
possible if the oxygen be in carbonyl, CO, where it is in com- 
bination with carbon by both affinities, C=0. The simplest 
aldehyd is formic aldehyd, CH 2 0, and there is but one way of 

/TT 

expressing its constitution graphically: H— (X n - The peculiar 

/TT 

properties of aldehyds are due to the group — C\ n ' Acetic 

/TT 
aldehyd then becomes CH 3 — (X • Under certain conditions for- 
maldehyd forms additive compounds as if it were not wholly sat- 
urated: its valence at such times is expressed by the graphic 

/TT 

formula H— C<^ __* 



ALDEHYDS 407 

Formaldehyd, H . COH or CH 2 0, can be formed by oxidizing 
methyl alcohol vapor, through the catalytic agency of incan- 
descent platinum. This reaction is much accelerated when 
the platinum is finely divided, as spongy platinum. When cal- 
cium formate is heated formaldehyd comes off as a vapor: 

Ca(H.C0 2 ) 2 = CaCO s + H . COH. 

It is a colorless gas with a strong pungent odor, and condenses 
at —2i° C. ( — 5-8° F.) to a colorless liquid. It is readily soluble 
in water, making a colorless volatile liquid which is a convenient 
preparation for medicinal use. The 40-per cent, aqueous solution 
is called liquor )ori?ialdehydi, U. S. P., and sometimes formalin. By 
heat it evolves the gas with some steam. It is of great value in 
hardening and preserving anatomic specimens and as a germicide, 
antiseptic, and deodorizer. The aldehyds are unstable, and not 
being saturated compounds they readily join to other elements or 
groups. Intermediate between alcohols and acids, they take oxy- 
gen to form the latter or give up oxygen to make the former. 
Thus: 



CH 2 


+ 





= CH 2 2 (Formic acid). 


CH 2 


+ 


H 2 


= CH 4 (Methyl alcohol). 


CH 2 


V 


NH 3 


= CH 3 ONH 2 (Aldehyd ammonia). 


CH 2 


+ 


H 2 S 


= H 2 0-hCH 2 S (Sulphaldehyd). 



Like other lower aldehyds it forms an additive compound with 
sodium bisulphite which is soluble. 

For disinfecting a closed room the liquor jormaldehydi may 
be vaporized by heat or sprayed. The vapor combines directly 
with the albumin of the bacterial cell and destroys its reproductive 
powers. An approved method known as permanganate formalin 
depends upon the fact that potassium permanganate oxidizes a 
portion of the formaldehyd to formic acid, liberating enough 
heat to evaporate the remainder. A deep tin pail is warmed 
and then receives the permanganate as crystals or powder, 8J oz. 
for every 1000 cu. ft. of room space. Upon this 20 fl. oz. of for- 
malin is poured. Effervescence begins at once, the room is closed, 
and the operation is over in five or ten minutes without the use of 
a lamp. After twelve hours the room is opened and the odor 
removed by sprinkling ammonia. 

Paraformaldehyd [(CH 2 0)J {Tri-oxy methylene). — When for- 
maldehyd is evaporated or when moderately heated, 2 or more 
molecules join to make a polymeric modification. This is a color- 
less, amorphous substance, melting at 171 ° C. (339 ° F.), subliming 
at a slightly higher temperature, and when strongly heated breaking 



408 ALIPHATIC COMPOUNDS 

up into gaseous formaldehyd. As the gas cools paraformaldehyd 
is again obtained. The formation of the gas may be shown by 
Schiff's reaction, using paper wet with decolorized fuchsin (see 
Tests). 

Polymerism is the condition of a substance where the molecules 
in their original proportion are aggregated into a more complex 
group. The different modifications are similar to the allotropic 
forms of elements, and their relationship to one another resembles 
that of yellow and red phosphorus. The constitution of the 
polymer of formaldehyd, (CH 2 0) 3 , is usually represented by the 
graphic formula below, the dotted lines showing the method of 
union: 



H— CH /CH— H 



t\l 

\X 

CH '• 

I 
H 

Toxicology of Formaldehyd. — In spite of its reputation as 
a disinfectant harmless to man, there are many instances of inflam- 
mation of the conjunctiva and air-passages among those who manu- 
facture formaldehyd, or who breathe its vapor when disinfecting 
houses. The higher animals are injured, if not killed, by the vapor 
when it is present in sufficient strength to destroy infectious germs. 
Under the names preservalene and jreezene it is widely used by 
dairymen to preserve milk in hot weather. In any but the smallest 
amounts it inhibits the action of the digestive ferments and causes 
indigestion and imperfect assimilation. Very small amounts suf- 
fice to preserve milk for several days with very little retarding 
effect on digestion, but the mixture should be labeled preserved. 
(See Milk, p. 568.) 

Symptoms. — Solutions containing 1 part in 2000 irritate the 
skin, causing eczema, ulcerations, and even gangrene. When the 
40 per cent, liquid is taken in doses of J oz. or more, the symp- 
toms are pain in the mouth and abdomen, vomiting, giddiness, 
diarrhea with straining, urinary suppression, and recovery or, 
may be, death by dyspnea and syncope. 

Treatment. — After evacuating the stomach dilute spirits of 
ammonia will be of help. The odor of its vapor in a room is at 
once removed by ammonia vapor. 

Test. — For detection of the presence of formaldehyd in milk 
see p. 569. When in a solid form, the material, minced, is digested 
for an hour at 80 ° C. (176 F.) in water acidified with sulphuric 



ALDEHYDS 409 

acid. Dry powdered sodium sulphate in excess is added, and the 
paste distilled. If the first portions of the distillate contain for- 
maldehyd, it will respond to the following tests: 

Schiffs Fuchsin Reaction. — Dissolve 0.2 gm. of rosanilin or 
the hydrochlorid in 10 c.c. of a freshly prepared, saturated aqueous 
solution of sulphur dioxid. Allow the solution to stand until all 
signs of pink disappear and it becomes colorless or pale yellow. 
Then dilute with water to 200 c.c. and preserve for use in a tightly 
stoppered bottle. It turns pink or violet with formaldehyd. 

With light excluded, the reagent keeps well. If necessary its 
sensitiveness may be restored by addition of sodium acetate till a 
pink color appears, which is discharged by a few drops of the 
original reagents. Not only do aldehyds redden it, but also 
alkaline solutions, heat, or prolonged exposure to the air. 

When the formaldehyd is in a gaseous state, the test may be 
applied by hanging in the air filter-paper wet with the reagent. 

Resorcin Test. — Having made a solution of 5 parts of resor- 
cin in 100 of potassium hydroxid (40 per cent.), a portion is 
heated with an equal volume of formaldehyd, and a red color is 
obtained. 

Acetaldehyd (CH 3 .COH) (Acetic Aldehyd).— This is formed 
by the oxidation of ethyl alcohol in the operation of distilling a 
mixture of alcohol, manganese dioxid, and sulphuric acid. The 
distillate is a mixture which is redistilled below 50 C. (122 ° F.). 
The second distillate is mixed with ether and saturated with am- 
monia to get a crystalline precipitate of aldehyd ammonia. This 
substance, distilled with dilute sulphuric acid at a low temperature, 
yields a dilute aldehyd. The water is removed with calcium 
chlorid. Acetic aldehyd is a colorless, volatile, inflammable liquid, 
boiling at 20. 8° C. (69 F.). Its odor is suffocating, like that of 
sulphur dioxid. It is soluble in water, alcohol, and ether, and 
acts as a reducing agent on ammoniacal solutions of silver. 

The formation of aldehyd from ethyl alcohol by abstracting 
H 2 is shown in equation (1); in equation (2) is shown how acetic 
acid is formed by oxidation of the aldehyd: 

H H H H 

I I I I I 

(i) H— C— C— O-i-H -f O = H— C— C = + H 2 
W ^ « 

Ethyl alcohol. Acetaldehyd. 

H H H O.H 

II II 

(2) H— C— C = + = H— C— CHO 

H H 

Acetaldehyd. Acetic acid. 



4IO ALIPHATIC COMPOUNDS 

Acetic aldehyd is a rapid intoxicant, inducing profound stupor 
and deleterious after-effects, such as attend the drinking of high 
wines — raw spirits which have not been deprived of it, as they 
should, before being taken internally. 

Three polymerids of aldehyd are known: aldol, (C 2 H 4 0) 2 ; 
paraldehyde (C 2 H 4 0) 3 ; and metaldehyd, (C 2 H 4 0) n . 

Paraldehyd is formed when a drop of sulphuric acid is added to 
aldehyd. There is violent action and a change to a more pleasant- 
smelling liquid with a burning taste, boiling at 124 C. (255 °F.) 
and solidifying by cold. It is soluble in water, and if distilled with 
dilute sulphuric acid goes back to aldehyd. 

Toxicology. — Its physiologic effects in doses of 30 to 60 min. 
(2-4 c.c.) are those of a soporific like chloral, but with less depres- 
sion of the heart. It gives a strong disagreeable odor to the 
breath and the urine. A very large amount, such as 3 fl. oz. 
(90 c.c), will cause nausea, vomiting, vertigo, headache, ending in 
profound stupor. Habitual use of it in doses of 2 oz. (60 c.c.) 
leads to a deplorable condition, characterized by mental weakness, 
dyspepsia, sleeplessness, and delusions. 

Treatment. — The indications are the same as in poisoning from 
chloral. 

Detection. — Paraldehyd does not give the reactions nor show 
the ordinary properties of aldehyd. It must first be converted to 
aldehyd by distilling with steam, the suspected material having 
been first acidified by sulphuric acid. The distillate should give 
Schiff's reaction with fuchsin (see Formaldehyd, p. 407). 

Tollen's Test. — A deposit occurs of a silver mirror on the glass 
of a test-tube that has been cleaned with hot caustic soda and 
washed with distilled water, when weak aldehyd is added to am- 
moniacal solution of silver oxid: 

CH 3 . COH + Ag 2 = CH3CO . OH + 2 Ag. 

This is a very sensitive test. The reagent is made by dissolving 
3 gm. of silver nitrate in 30 gm. of 25 per cent, ammonia water 
and adding 3 gm. of sodium hydroxid dissolved in 3 c.c. of water. 

Chloral (CC1 3 . COH) {Trichlor aldehyd).— This most important 
derivative of acetic aldehyd is prepared by saturating absolute 
alcohol with dry chlorin. The first product is a crystalline sub- 
stance which is shaken with sulphuric acid and distilled. The 
distillate treated with lime and again distilled yields chloral. The 
syllable -al used as a suffix indicates an aldehyd. Thus acetic 
aldehyd is sometimes called ethanal, to indicate that it is the alde- 
hyd formed from ethanol (ethyl alcohol). Chloral is an abbrevia- 
tion for chlorethanal. The first effect of chlorin is to convert the 



ALDEHYDS 4II 

alcohol to aldehyd by extracting two hydrogen atoms to make 
2HCI; the second is to chlorinate the aldehyd: 

CH3COH + 3 C1 2 = CCl 3 COH + 3HCI. 

Aldeyhd. Choral. 

Chloral is a colorless oily liquid with a pungent odor and acrid 
taste. Its reactions show it to be an aldehyd in its chemical 
properties. It is soluble in water, and in a small amount of the 
solvent it forms a colorless crystalline compound, chloral hydrate, 
CCI3COH . H 2 0. 

On heating with an alkali, chloral yields chloroform and a 
formate: 

CCI3COH + KOH = CHCI3 + H.COOK 

Chloral. Chloroform. Potassium formate. 

Chloralum hydratum (U. S. P.) occurs as volatile crystals 
having a odor like that of a melon and a taste the unpleasant 
nature of which is masked by solution in beer, whisky, or wine. 
It is soluble in water, alcohol, and ether. Dose: 10 to 25 gr. 
(0.66-1.62 gm.). It is incompatible chemically with alcohol, potas- 
sium iodid, carbolic acid, and camphor. 

Toxicology. — Acute poisoning occurs from accidental over- 
dosing, also from criminally mixing it with the drink of a victim, 
when it is known as knock-out drops. At no stage does it exhila- 
rate like alcohol, nor does it relieve pain like chloroform until a full 
hypnotic dose has caused sleep. With massive doses the soporific 
effects are much like those of heavy doses of alcohol or chloroform. 
The skin is cold and clammy; the brain and spinal centers are 
depressed and finally paralyzed. As a gastric irritant it may first 
cause nausea and vomiting, but deep coma soon sets in with 
thready pulse and feeble respiration, growing more shallow and 
irregular until it ceases altogether. Chronic poisoning is quite 
common, the habit of chloral tippling being formed to cure insom- 
nia. In time varied symptoms are produced, such as indigestion, 
wasting, skin eruptions, conjunctivitis, pains, wakefulness, ner- 
vous depression with melancholia, and death from heart failure. 

Dose. — The maximum safe dose is 20 gr. (1.29 gm.), repeated 
twice at intervals of an hour. 

Postmortem Appearances. — Characteristic changes are not found 
at the autopsy. 

Treatment. — The stomach should be promptly evacuated and 
washed out with warm alkaline water. If no tube be at hand, 
then apomorphin, in hypodermic doses of 5 min. of a 2 per cent, 
solution, or other emetics, may be used. To rouse the heart 



412 ALIPHATIC COMPOUNDS 

strong coffee may be given by mouth or rectum, and hypodermic 
injections of 2 or 3 min. of a 2 per cent, solution of strychnin 
nitrate. Applications of hot bottles and blankets, flicking the face 
with a wet towel, artificial respiration, and oxygen, are measures 
that may prove of service to combat the depression. 

Fatal Dose. — Three grains have proved fatal to a child one 
year old. Ten grains have proved fatal to a woman of seventy 
with a weak heart. On the other hand, recovery has followed 
doses of more than half an ounce. 

Tests. — In the urine some chloral is eliminated unchanged, but 
most of it forms a compound with glycuronic acid called uro- 
chloralic acid, which may be mistaken for glucose, as it reduces 
the copper sulphate of Fehling's solution. As urochloralic acid 
and its salts are levorotatory to polarized light, by means of the 
polariscope we can distinguish between "chloral urine" and 
"sugar urine," which is dextrorotatory. If the urine be acidified 
with sulphuric acid and shaken with ether in a separating funnel, 
the ether takes up the chloral and on evaporation leaves it as a 
solid residue. The contents of the stomach should be digested 
for twenty-four hours with four volumes of absolute alcohol 
acidified with sulphuric acid; then filtered and evaporated. Petro- 
leum ether will remove fat and sulphuric ether will extract the 
chloral. 

Tests may be applied to the ethereal residue. Strong alkalis 
warmed convert chloral to chloroform, yielding the familiar odor 
of that substance. The chloroform may be identified by the 
Ragsky process, the betanaphthol test, and the offensive isobenzo- 
nitril test (pp. 388, 389). 

Chloral, having in it the group COH, like other aldehyds, 
reduces Fehling's solution (p. 602). 

To determine the quantity of chloral dissolved magnesia is 
first used to neutralize acids, and a measured amount of normal 
solution of sodium hydroxid is added to render the solution dis- 
tinctly alkaline. The excess is estimated by a normal oxalic-acid 
solution, and, subtracted from the original amount, gives the pro- 
portion taken up by the chloral. For 1 c.c. of normal sodium 
hydroxid that has united with the chloral calculate 0.1655 gm. of 
chloral. 

KETONES (Acetones) 

The interesting substance called acetone, or dimethyl ketone, 
CH 3 . CO . CH 3 , belongs to a class of compounds produced by 
the incomplete oxidation of secondary alcohols (p. 400). If sec- 
ondary propyl alcohol be oxidized, 2 atoms of hydrogen are ab- 
stracted, just as when a primary alcohol is so treated. But the 



KETONES 413 

primary alcohol forms an aldehyd, while the secondary alcohol 
forms a ketone. Thus: 

^ 3 >CHOH + O = CH >CO + H2 °' 

Secondary propyl Acetone, 

alcohol. 

All ketones are regarded as containing divalent carbonyl, ZZCO, 
linking together 2 hydrocarbon radicals. A mixed ketone is one 
which contains 2 different radicals, as methylethyl ketone, CH 3 . 
CO . C 2 H 5 . Both ketones and aldehyds may be regarded as 
derived from the paraffins by substituting 1 atom of oxygen for 
2 atoms of hydrogen; they are, therefore, isomeric. Thus, C 3 H e O 
is the empiric formula for acetone, CH 3 . CO . CH 3 , and also for 
propaldehyd, CH 3 . CH 2 . COH. The difference of constitution 
is shown by the further action of oxygen, which causes a ketone 
to break up into a mixture of two or more acids, but unites with 
an aldehyd to make a single corresponding fatty acid. They 
have, however, many resemblances in chemical behavior, such as 
the similar reaction with phosphorus pentachlorid, explicable from 
the fact that both contain the carbonyl group (p. 406): 

Acetone, ™ 3 >C=0. Aldehyd, JS >C=0. 
Cti 3 ^^3 

Ketones are more stable than aldehyds, as they have no avail- 
able hydrogen left for oxidation; they do not reduce alkaline 
solutions of copper and other metallic salts, nor do they combine 
directly with alcohols or with ammonia. They do not polymerize, 
as do the aldehyds. Their names always have the suffix -one. 

Acetone is the most important ketone. It can be prepared 
by the dry distillation of sugar, tartaric acid, or the acetates: 

Ca(CH 3 C0 2 ) 2 = (CH 3 ) 2 CO + CaC0 3 . 

Calcium acetate. Acetone. 

It is a mobile, colorless liquid, with a pleasant ethereal odor, spe- 
cific gravity 0.792. It boils at 56 ° C. (132.8 ° F.), is miscible with 
water, alcohol, and ether. It dissolves fats, resins, and guncotton. 
In diabetes and some other diseased states it exists in the blood 
and urine, and its peculiar odor may be detected on the breath. 
With its congeners, diacetic acid and oxybutyric acid, it is prob- 
ably formed from diabetic sugar and contributes to bring on the 
symptoms of diabetic coma. 

Tests for Acetonuria. — (1) Distil 25 c.c. from 500 c.c. of urine, 
which has been acidulated with phosphoric acid to prevent frothing, 



414 ALIPHATIC COMPOUNDS 

and apply the iodoform test by adding a small quantity of iodin 
and dropping in potassium hydroxid until the iodin color disap- 
pears. The odor of iodoform is recognized, and soon a yellow 
crystalline precipitate appears. 

(2) Without distilling, add to the urine an excess of a solution 
of 5 gm. of fresh mercuric oxid in 100 c.c. of 2 per cent, sulphuric 
acid. By filtration remove the precipitate and boil the filtrate for 
several minutes. A white precipitate or even a cloudy appearance 
denotes acetone. 



SULPHUR DERIVATIVES OF THE PARAFFINS 

Not only does sulphur form a series of mineral compounds 
parallel with those of oxygen, but also a class corresponding to 
the simple ethers, alcohols, aldehyds, acids, and ketones, which 
are oxygen derivatives of the paraffins. These are named from 
theion (sulphur) as //wValcohols, thio-ethers, //^0-aldehyds, thio- 
acids, //^-ketones. In addition, sulphur forms compounds which 
have no oxygen counterpart, such as the sulphoxids, sulphones, 
and sulphonic acids. Two classes of compounds are formed by 
the action of hydrogen sulphid upon the alcohols — namely, hydro- 
sulphids and sulphids. The relationship of these to alcohols and 
ethers is shown by the formulas: 

Ethyl alcohol or hydroxid C 2 H 6 . OH. 

Ethyl thio-alcohol or hydrosulphid C 2 H 5 . SH. 

Ethyl ether or oxid (C 2 H 5 ) 2 0. 

Ethyl thio-ether or sulphid (C 2 H 5 ) 2 S. 

The thio-alcohols or organic hydrosulphids have been long 
known as mercaptans (mercurium captans) because they readily 
seize on mercuric oxid to form crystalline compounds, called 
mercaptids or thio-ethylates: 

2 C 2 H 5 .SH + HgO = (C 2 H 5 .S) 2 Hg + H 2 0. 

Ethyl mercaptan. Mercuric mercaptid. 

Ethyl Mercaptan (C 2 H 5 . SH) {Thio-alcohol).— This substance 
has become important as the material from which the drug sul- 
phonal is made. It is prepared by the action of ethyl chlorid on 
potassium hydrosulphid: 

C 2 H 5 C1 + KHS = C 2 H 5 . SH + KC1. 



SULPHUR DERIVATIVES OF THE PARAFFINS 415 

It is a colorless neutral liquid, with an unpleasant odor, like 
that of garlic. It boils at 36.2 ° C. (97.2 ° F.). Other mercaptans 
are obtained by similar reactions. They all have disagreeable 
odors, and in chemical properties resemble ethyl mercaptan. 

Thio-ethers or sulphids, like ethyl sulphid (C 2 H 5 ) 2 S, are made 
by distilling salts of ethyl sulphuric acid with potassium sulphid: 

2 C 2 H 5 .KS0 4 + K 2 S = (C,H-) 2 S + 2 K 2 S0 4 . 

Ethyl potassium sulphate. Ethyl sulphid. 

Slllphonic acids are acids containing the group S0 2 . OH 
attached to a hydrocarbon radical by the sulphur atom and not 
by the oxygen, as in sulphites, thus: 

S° /OC 2 H 5 

\OH \OC 2 H 5 

Ethyl sulphonic acid. Ethyl sulphite. 

They are obtained by oxidation of mercaptans with nitric acid: 
C 2 H 5 .SH + 30 = C 2 H 5 .S0 2 .OH 

Ethyl mercaptans. Ethyl sulphonic acid. 

They are strong acids, which unite with metals instead of the 
hydrogen of hydroxyl, forming salts like potassium ethyl sulpho- 
nate, C 2 H 5 . S0 2 . OK. 

Mercaptols (thioketones) are formed by the union of ketones 
and mercaptans: 

CH s ^ rr . , C 2 H 5 .SH _ CH 3 ^ r ^C 2 H 5 S , ua 
CK 3 ^ U + C 2 H 5 .SH — CH^^QHjS + ^^ 
Acetone. Ethyl mercaptan. Ethyl mercaptol. 

When a mercaptol is oxidized the product is a sidphone, such 
as sulphonmethane "sulphonal" and sidphonethylmethane "trional." 
Sulphonmethanum (Diethylsulphone-dimethylmethane). — This 
is formed by oxidizing ethyl mercaptol with potassium permanga- 
nate: 

CH 3 . .C 2 H 5 S , Q _ CH 3 . r<r C 2 H 5 S0 2 
CH 3 >C ^C 2 H 5 S "+" 4U — CH s - >u ^-C 2 H 5 S0 2 

Ethyl mercaptol. Sulphonal. 

It is obtained in colorless, tasteless prismatic crystals, sparingly 
soluble in cold water or cold alcohol, but quite soluble in hot 
water or hot alcohol. It is used as a hypnotic, having the same 
properties as paraldehyd, though more uncertain because of its 
insolubility in water. Dose: 20 to 40 gr. (1.25-2.50 gm.). 

Toxicology. — The symptoms due to excessive doses are: Stupor, 
insensibility, sometimes preceded by convulsions; the breathing 



416 ALIPHATIC COMPOUNDS 

is irregular, pulse weak, and skin cyanotic. Death may be due to 
failure of respiration or to suppression of urine. In lingering cases 
the urine is red from the hematoporphyrin of dissolved blood. 
The sulphonal habit has caused this symptom with albuminuria, 
eruptions, and impairment of mind and locomotion. Chronic 
poisoning from long-continued small doses is attributable to the 
slow elimination by the kidney, causing a cumulative action. 

Fatal Dose and Period. — Death has been caused by 30 gr. 
(1.94 gm.), yet recovery after ninety hours of sleep has followed 
a dose of 3 oz. (93 gm.). A fatal result in a few hours or days 
would probably follow 75 gr. (4.85 gm.). 

Treatment. — The stomach should be evacuated with a siphon 
tube, using hot water, and the intestines emptied with purgatives. 
Hypodermic injections of strychnin are useful to sustain the 
heart and respiration. 

Detection. — Owing to its remarkable stability, urinary or post- 
mortem isolation is not difficult. It is accomplished by making 
an alcoholic extract of the material, evaporating, extracting the 
residue with hot water, evaporating, and finally extracting the 
residue with ether. The tests are applied to the residue of this 
last extraction. 

Test. — Mixed with powdered charcoal and heated in a test- 
tube, sulphonal is reduced and breaks up into mercaptan (detected 
by garlicky odor); formic and acetic acids (the vapor reddens 
litmus paper), and sulphur dioxid (which bleaches paper wet with 
blue-starch iodid). 

Trional, Sulphonethylmethanum, U. S. P. (Diethylsulphone- 
methylethyl methane) . — This syllable tri- is used because there are 
three ethyl groups in the compound, while sulphonal has only two: 

C2H 5 -^p^-S0 2 • C 2 H 5 
CH 3 - ;>u ^S0 2 .C 2 H 5 - 

It is a white powder with a faint, bitter taste. It is sparingly 
soluble in water, and resembles sulphonal in its effects, but is more 
hypnotic. Dose: 7 to 30 gr. (0.5-2 gm.). It has caused death 
with symptoms like those of sulphonal. 

Tetronal (Diethylsulphone-diethylmethane). — In this sulphonal 
compound there are four ethyl groups, each addition of ethyl 
increasing the hypnotic power: 

C 2 H 5 -^ r ,^S0 2 . C 2 H 5 
C 2 H 5 ^ c< -S0 2 .C 2 H 5 - 

It is used like sulphonal. Dose: 7 to 30 gr. (0.5-2 gm.). 

It is a narcotic poison with symptoms like those of sulphonal. 



FATTY ACIDS 417 

FATTY ACIDS 

The relationship of the fatty acids to other oxygen derivatives 
of the paraffins is shown in the structural formula of the second 
member: 

C 2 H 6 C 2 H 5 .HO CH3.COH CH3.COOH 

Ethane. Ethyl alcohol. Acetic aldehyd. Acetic acid. 

In another place (p. 409) are the equations for the stages of 
oxidation from an alcohol to an acid by way of an aldehyd. The 
aldehyd group, — COH, receiving an addition of oxygen, be- 
comes — CO OH, carboxyl, and the reactions of the substance 
change from those of an aldehyd to those of an acid. As the 
higher members of the acid series are components of animal and 
vegetable fats, the entire class is called fatty, or aliphatic. 

The first acid, formic, H . COOH, has an atom of hydrogen 
which does not ionize joined to the carboxyl, which contains 
another atom of hydrogen that is ionizable. Like the other 
members of this large series it is a volatile liquid, miscible with 
water, and having a strong acid reaction. In the succeeding 
members the non-ionizable hydrogen is replaced by an alkyl 
radical, such as methyl (CH 3 ) or ethyl (C 2 H 5 ), the molecular 
weight increasing by CH 2 , the boiling-point rising and the spe- 
cific gravity falling as they ascend. The higher compounds are 
light, solid, waxy substances without pungent odor, insoluble in 
water and having very little acid property. 

The hydrogen of carboxyl only is replaceable by metals or 
basic radicals, forming salts. If replaced by an alcoholic radical, 
the product is called a compound ether. The basicity of an organic 
acid is in accordance with the number of carboxyl groups it con- 
tains. The fatty acids are monobasic, but some other organic 
acids are dibasic and some are tribasic, forming normal acid, 
and basic salts. Sometimes the basicity is indicated by a formula 
which sets apart the hydroxyl, all the remainder being called the 
acid radical; thus, C 2 H 3 is called acetyl when acetic acid is 
written C 2 H 3 . HO. The general formula for the fatty acids is 
C n H 2n+1 CO . OH. 

Occurs in 

Nettles and ants. 

Organic decompositions, vinegar. 

Urine, sweat. 

As glycerid in butter. 

Valerian plant. 

As glycerid in butter. 

As glycerid in palm oil, solid fats. 

As glycerid in stearin, lard, tallow. 

r 
27 



Fatty acids. 


Melts at 




C. F. 


Formic, H . COOH 


8-3° (47°) 


Acetic, CH 3 . COOH 


16.5 (62°) 


Propionic, C 2 H 3 . COOH 


—2 4 ° (—11.2°) 


Butyric, C 3 H- . COOH 


-4° (24-8°) 


Valeric, C 4 H 9 .COOH 


-16° (3.2 ) 


Caproic, C 5 H U . COOH 


—2° (28.4°) 


Palmitic, C, 5 H 31 .COOH 


62 (143-6°) 


Stearic, C 17 H 35 . COOH 


6 9 ° (158°) 



418 ALIPHATIC COMPOUNDS 

Nine acids of no medical importance come between caproic 
and palmitic. The higher members end in melissic acid, 
C 29 H 59 COOH, found in beeswax. 

Formic Acid. — This was first observed in the stinging liquid 
ejected by the ant (formica). It is also found in the stings of the 
nettle. When carbon monoxid is passed over gently heated 
potassium hydroxid, potassium formate is obtained: 

CO + KOH = H.COOK. 

The acid is set free by distilling the formate with sulphuric 
acid. The usual method of preparing it is by heating oxalic acid 
with glycerin. The formic acid at once combines with the glyc- 
erin, which readily gives it up on distillation. Oxalic acid has 
two carboxyl groups and breaks up as shown in the formula: 

1COOH = H.COOH -f C0 2 . 

I.. i : 

COO;H 

Proof that formic acid is closely related to carbonic acid is 
found by the action of carbonic-acid water on potassium: 

2 H 2 C0 3 + 2 K = K.C0 2 H + KHCO3 + H 2 0. 

Potassium formate. Potassium carbonate. 

Properties. — Formic acid is a colorless, volatile liquid with a 
peculiar pungent odor, marked acid properties, and highly irritat- 
ing local effects. 

Tests. — Its powerful deoxidizing action enables it to precipitate 
metallic silver from warm ammoniacal solutions of the oxid (see 
Tollen's reagent, p. 410). This reducing power is due to the 

°^ 
aldehyd group shown in its structure /C — OH. The other 

H' 
fatty acids are not reducing agents because they do not have the 
aldehyd group seen in the formic-acid formula. Heated with 
concentrated sulphuric acid, H 2 is abstracted, freeing CO. This 
proves that carbon monoxid is an anhydrid of formic acid: 

CH 2 2 = H 2 + CO. 

Acetic acid, CH 3 .COOH, is so readily formed by natural 
fermentations that its general properties have been known from 
the earliest times. Other substances discovered later to have 
a similar sharpness in taste were given the name acids, derived 
from the same root word. Its synthesis starts with the action of 
iodin on methane, making methyl iodid CH 3 I. In the presence 
of potassium cyanid this changes to methyl cyanid. Thus: 

CH3I + KCN = CH 3 .CN + KI. 



FATTY ACIDS 



419 



Boiling methyl cyanid with a dilute mineral acid causes it to 
react with water and vield acetic acid and ammonia: 



CH S .C-JN + hS H = CH 3 c/^ + NH 3 . 

Methyl cyanid. Water. Acetic acid. 

The above series of reactions constitutes strong proof that the 
structural formula of acetic acid must include methyl, CH 3 , and 
hydroxyl associated with carbonyl in the formula — 

Vinegar Method. — Acetic acid is produced on a large scale in 
vinegar making. Oxidation of ethyl alcohol results from the 
influence of a microscopic unicellular plant, Mycoderma aceti, 
which in large masses is called mother oj vinegar. To facilitate 
the process of conveying oxygen from the air the natural alcoholic 
liquor, weak wine, cider, or beer is made to trickle slowly through 
a ventilated cask over shavings already wet with old vinegar. 

Pyroligneous Method. — Among the products of dry distilla- 
tion of wood are methyl alcohol (wood spirits) and acetic acid. 
The acid is fixed with lime, forming calcium acetate, the other 
volatile products being distilled off. Distilled with sulphuric acid, 
the acetic acid separates in the distillate. By repeated distillations 
and freezing this is purified and freed from water to make anhy- 
drous acetic acid. 

A little water remains (not more than 1 per cent.) in the com- 
mercial acid known as glacial acid or acidum aceticum glaciate. 
This is a colorless crystalline solid with an irritating odor, melting 
at 15 ° C. (59 F.) to form a strongly acid liquid soluble in water, 
alcohol, and ether. 

Acidum aceticum, U. S. P., contains only 36 per cent, of the 
anhydrous acid, and acidum aceticum dilutum, U. S. P., has 6 per 
cent. 

Vinegar. — In the household a mixture containing from 3 to 6 
per cent, of acetic acid is commonly used. The flavor and the 
color of the vinegar varies somewhat according to its source — 
wine, cider, beer, or an artificial mixture of essences and coloring 
matter with dilute acetic acid. Should mineral acids be used as 
adulterants, they can be detected by the tests mentioned in other 
places. 

Tests for Acetic Acid. — It has a characteristic odor. When 
heated with alcohol and sulphuric acid it develops the agreeable 
odor of acetic ether. With ferric chlorid it yields a deep red color 



420 ALIPHATIC COMPOUNDS 

which, when boiled, changes to a red-brown precipitate of ferric 
subacetate. 

Chloracetic Acids. — One, two, or all three hydogen atoms 
in the methyl group of acetic acid may be substituted by chlorin, 
making the three acids monochlor acetic, CH 2 ClCOOH; dichlor- 
acetic, CHCl 2 COOH, a colorless liquid used in medicine; and tri- 
chloracetic, U. S. P., CCI3COOH, a crystalline substance used as a 
reagent for albumin. It is deliquescent, has a pungent odor, and is 
soluble in water, alcohol, and ether. It is a local caustic used 
to destroy warts and other cutaneous growths. 

Butyric Acid. — Two isomeric forms are known of the for- 
mula C 3 H 7 COOH. Normal butyric acid occurs in animals and 
vegetables, sometimes free, but more often as an ester with glyc- 
erin. This ester, butyrin, is characteristic of butter, from which 
butyric acid is set free by the rancid fermentation. This acid 
gives the rancid odor and flavor. When milk sours, lactose is 
converted into lactic acid by the lactic ferment: 

Ci 2 H 22 O n + H 2 = 4C 3 H 6 3 

Lactose. Lactic acid. 

By adding decaying cheese the lactic acid is broken up by the 
butyric ferment: 

2C 3 H 6 3 - C 4 H 8 2 + 2 C0 2 + 2H 2 . 

Lactic acid. Butyric acid. 

Butyric acid is a thick, sour, colorless liquid, smelling like stale 
perspiration or rancid butter. It mixes with water in all pro- 
portions and boils at 163 ° C. (325. 4 F.). 

Valeric Acid (C 4 H 9 . COOH).— Of the four isomeric forms 
known, two of them occur in the plants valerian and angelica 
root, and the mixture obtained by distillation of valerian is the 
valeric acid used in medicine. This is an oily liquid boiling at 
174 C. (345.2 ° F.) and forming valuable medicinal salts — the 
valerates of zinc, ammonium, iron, and quinin. 

Palmitic acid, C 15 H 31 COOH, and stearic acid, C 17 H 35 . COOH, 
occur abundantly in animal and vegetable fats as glycerin esters 
of palmitin and stearin. In stearin candle-making these are pre- 
pared on a large scale. They are waxy, colorless solids, melting 
respectively at 62 ° C. (143.6 F.) and 69 ° C. (156.2 ° F.). They 
are soluble in alcohol and ether, but insoluble in water. 

Margaric acid, C 16 H 33 COOH, does not occur in nature, 
though the name was formerly given to a mixture of palmitic and 
stearic acids. It is now reserved for an acid which is prepared 
artificially. 



ORGANIC ACIDS, NOT FATTY 42 1 



ORGANIC ACIDS, NOT FATTY 

Oleic acid, U. S. P., C 17 H 33 . COOH, belongs to the acrylic acids, 
which differ from the fatty acids as the olefins from the paraffins. 
It is usually found in plants and animals, associated with palmitic 
and stearic acids as glycerin esters. 

In the process of soap-making this acid is produced from fats. 
The other acids crystallize, leaving oleic acid as an oily liquid at 
temperatures above 14 C. (57.2 ° F.). 

Oxalic Acid, U. S. P., (H 2 C 2 4 ).— Glycol, C 2 H 4 . (OH) 2 , has 
been described (p. 401) as a dihydric alcohol containing two 
hydroxyl groups. As a primary alcohol it yields on oxidation an 
acid with one carboxyl group — glycollic, CH 2 (OH)COOH, 
and a remaining alcohol group, CH 2 OH, thus forming a hydroxy- 
or alcohol-acid. Another acid is formed when it is more com- 
pletely oxidized with two carboxyl groups, oxalic acid, 2 (CO OH): 

CH 2 OH COOH 

I + 20 2 = I + 2H 2 0. 

CH 2 OH COOH 

Glycol. Oxalic acid. 

It is dibasic, making two series of salts, neutral and acid oxalates, 
which are fully discussed in another place (p. 200). 

Succinic Acid, H 2 C 4 H 4 4 . — There are two isomers of this acid 
namely: 

CH 2 COOH CH(COOH) 2 . 

Ordinary succinic | ; isosuccinic | 

CH 2 COOH CH 3 

They are distinguished by heating to 150 C. (302 ° F.); the ordi- 
nary acid is not changed, but the isosuccinic splits to form pro- 
pionic acid and carbon dioxid. A trace of the ordinary acid is 
produced in alcoholic fermentation and is also found in the gastric 
contents when mould is present. 

Detection. — The gastric contents are shaken with ether, which 
is then separated by a funnel and evaporated to dryness. The 
residue is dissolved in weak ammonia, the excess of ammonia 
then boiled off, and the neutral solution remaining is added to 
dilute ferric chlorid; a brown-red precipitate is formed by succinic 
acid. 

Glutaric Acid, COOH(CH 2 ) 3 COOH.— Normal pyrotartaric, 
the next member of the homologous series with succinic acid, 
crystallizes in large plates, soluble in water. It forms an amino- 
acid (glutamic) which is a constituent of proteid matter. 



422 ALIPHATIC COMPOUNDS 

HYDROXY- OR ALCOHOL-ACIDS 

Lactic Acid, U. S. P., (C 3 H 6 3 ) {Hydroxy propionic Acid).— It 
has been stated above that this acid is the characteristic product 
of the lactic fermentation occurring in sugar, starch, and other 
carbohydrates, when animal nitrogenous matter is present (see 
Butyric Acid, p. 420). It can be prepared also by oxidizing pro- 
pyleneglycol with nitric acid. Several acids are known of the same 

OTT 

molecular formula, and three are stereo-isomeric, CH 3 CH<p ( ^ ( ^TT* 

These are distinguished apart by differences of crystalline structure, 
solubility, and effects on polarized light. This last property gives 
the names, inactive, dextro-, and levo-rotatory lactic acids. 

Ordinary Lactic Acid {Inactive to Polarized Light). — This is the 
acid present in sour milk and in the gastric contents in the first half- 
hour of digestion (see pp. 544 and 552). The lactic acids are thick, 
sour liquids, miscible with water and alcohol in all proportions. 

From organic mixtures lactic acid can be separated by first 
acidifying with sulphuric acid and shaking with ether. This 
ethereal extract, underlaid with solution of ferric chlorid, gives 
at the line of contact a yellow band. It is a monobasic acid, 
forming metallic salts and esters known as lactates. It contains 
the alcoholic group, >>CH . OH and shows many of the reactions 
of a secondary alcohol. 

Sarcolactic acid (C 3 H 6 3 ) {paralactic acid, dextrolactic acid) 
occurs in the juices of muscles, and can be prepared from extract 
of meat. The constitution and chemical behavior are the same 
as those of ordinary lactic acid, but optically this acid is active, 
turning the polarized ray to the right. The acid rotating to the left, 
levolactic, is produced by a special ferment working on cane-sugar. 

Oxyblltyric Acid. — In the oxidation of secondary normal 
butyl alcohol (butanol), the first group only (CH 3 ) is oxidized to 
COOH. This must always be at either end of the chain to 

/OFT 

give the carbon atom the three valences needed for the ~C\r\ . 

The alcohol hydroxyl may be attached to any of the remaining C 
atoms, and thus make it a hydroxyacid or oxyacid. The rela- 
tive position of the HO group in the three possible oxybutyric 
acids are indicated below by the Greek letters (a) alpha, (/9) beta, 
(j[) gamma. 

COOH COOH COOH COOH 

I'll 
CH 2 a CHOH a CH 2 a CH 2 

CH„ £CH 2 0CHOH y3CH 2 

I I I I 

CH 3 7CH3 yCH 3 yCH 2 OH 

Butyric acid. a Oxybutyric acid. /3 Oxybutyric acid. y Oxybutyric acid. 



ORGANIC ACIDS, NOT FATTY 423 

The levo beta oxybutyric acid is especially interesting, as it is 
found associated with diacetic acid and acetone in the blood and 
urine of severe cases of diabetes. It is a factor in the acidosis of 
diabetic coma. 

Test. — Detection in the urine is not easy. Dependence is 
placed usually on the red ferric chlorid reaction given by its con- 
stant companion, diacetic acid. One method is to remove dex- 
trose from the urine by fermentation and then estimate the re- 
maining oxybutyric acid by its levorotation of the ray in the 
polariscope (p. 61). 

Tartaric acid, U. S. P., C 4 H 6 6 , is a constituent of a large 
number of plants, occurring in many fruits, such as the berries of 
the mountain ash, and particularly in grapes. In the making of 
wine the secondary fermentation in the cask causes the formation 
of a dark red deposit. This deposit, argol, or crude tartar, is 
an impure potassium bitartrate. By solution and recrystalliza- 
tion this is purified and then treated with chalk and calcium 
chlorid to form a precipitate of calcium tartrate. With dilute 
sulphuric acid the calcium is removed as insoluble sulphate and 
tartaric acid is left in solution. The solution is filtered off and 
crystallized in large colorless prisms without odor, but with a 
sour taste. This is the ordinary tartaric acid (dihydroxy-succinic 
acid), which is dibasic, forming neutral and acid tartrates, such 
as monopotassium tartrate, sodium potassium tartrate, and anti- 
mony potassium tartrate. 

By synthesis it can be built up in such a way as to indicate 
that its constitution consists of two similar groups united, as a 
dihydroxy-dicarboxylic acid: 

CH(OH)COOH 
I 
CH(OH)COOH 

The two dark carbon atoms are linked together at one point, 
but have different atoms or groups at other points. 

When substances of the composition C 4 H 6 6 having similar 
chemical properties are studied by polarized light, four different 
isomeric modifications are recognized: dextrotartaric, levotartaric, 
mesotartaric, and racemic acids. These examples of optic activity 
are regarded as proofs of the rule that it depends upon molecular 
asymmetry. 

Stereo-isomerism is isomerism explained by differences of 
arrangement in space of three dimensions. Ordinary tartaric acid 
crystallized from grape juice rotates the polarized ray to the 
right, but the remaining juice contains another acid, racemic, with 
the same formula, C 4 H 6 6 , and identical chemically, but different 



424 



ALIPHATIC COMPOUNDS 



physically, its solution being inactive to polarized light. The 
sodium-ammonium salts of these acids have the same composi- 
tion, Na(NH 4 )C 4 H 4 6 , and the same difference optically as their 
acids. The crystalline form of the tartrate is shown in D (Fig. 
78) while the racemate is found to crystallize in two forms, one 
like D, the other like L, each the reflected image of the other. 




ft 



>l 



Fig. 78. 



B L 

-Isomeric salts of tartaric acid: P=dextrorotatory; L=levorotatory._ 



The differences are in the arrangement of the small faces {a, b) f 
darkened in the figure. When the crystals of each kind are set 
apart, separately dissolved, and tested with the polariscope, the 
solution of D is found to be dextrorotatory, and that of L, levo- 
rotatory. There is then a dextrotartaric acid and a levotartaric 
acid. If these solutions of equal concentration be mixed, they 






.D-tartaric acid. 



/--tartaric acid. 
Fig. 79. — Isomeric forms shown by tetrahedral models. 



TOOff 
Mesotartaric acid. 



neutralize each other optically and racemic acid (D + L tartaric 
acid) is produced. 

From dibromsuccinic acid a fourth isomer, X, mesotartaric acid, 
is obtained. This is optically inactive, like racemic acid, but can 
not be split into the right- and left-handed acids. 

A study of the optically active substances shows that this 
property depends upon the presence in the molecule of an asym- 



ORGANIC ACIDS, NOT FATTY 425 

metric carbon atom — that is, one which is joined immediately to 
four different atoms or groups. Each of the four atoms or groups 
is supposed to be placed on one of four different lines drawn from 
the center of an imaginary tetrahedron to the four corners. 

If two tetrahedral models, representing two compounds, are 
manipulated it is found that the two asymmetric carbon atoms 
are capable of three distinct arrangements, corresponding to the 
three tartaric acids, the fourth being an externally compensated 
mixture of two others (Fig. 79). 

Three of the forms may be represented by the three different 
graphic formulas below, in which the solid black letter C stands 
for an asymmetric carbon atom. 



COOH COOH COOH 

H— C— OH OH— p— H H— C— OH 

OH— c— H H— c— OH H— c— OH 

I I i 

COOH COOH COOH 

Z)-tartaric acid. Z-tartaric acid. Mesotartaric acid. 

Using tetrahedral models for the black-letter carbon atoms, 
these compounds will be represented in the diagrams above (Fig. 
79), where the groups are arranged in space of three dimensions, 
thus giving a perfect illustration of stereo-isomerism. 

Citric acid, U. S. P., C 6 H 8 7 , is found free in the juice of the 
lemon, orange, gooseberry, raspberry, and many other sour fruits. 
It is prepared by boiling lemon juice and neutralizing with calcium 
carbonate. The calcium is fixed by sulphuric acid, leaving free 
citric acid in solution. The filtrate on evaporation deposits large 
colorless prismatic crystals, freely soluble in water. 

It is extensively used in pharmacy to prevent the precipitation 
of ferric hydroxid and other hydroxids from their salts. The 
solutions, thickened by evaporation and dried on glass plates, 
yield the brilliant scales which have given the name scale prep- 
arations to these compound tartrates and citrates. 

The synthetic reactions of this acid show that it is a hydroxy- 
tricarboxylic acid of the constitution: 

CH,' COOH 

I 

C(OH)- COOH 

I 
CH 2 - COOH. 

Being tr.basic, it forms three classes of salts, in which one, two, 
or three hydrogen atoms of the carboxyl groups are replaced by 
metals. 



426 ALIPHATIC COMPOUNDS 

Tests for Tartaric and Citric Acids. — Calcium chlorid yields 
a white precipitate with both. Boiling does not change citrates, 
but darkens tartrates. Potassium permanganate decolorizes tar- 
trates, but turns citrates green. 

KETONE-ACIDS 

These acids contain the CO of ketones as well as the CO OH of 
acids. The only one of medical interest is aceto-acetic acid, or 
diacetic acid, CH 3 CO . CH 2 COOH, which is associated with 
acetone in the urine and blood of severe cases of diabetes. It 
is a colorless syrupy liquid. It is believed to be derived in the 
blood from /S-oxbutyric acid CH 3 . CHOH . CH 3 . COOH by oxi- 
dation. It is called diacetic acid because two molecules of acetic 
acid are united in it by the elimination of H 2 0, thus: 



CH, . COOH-H;CH 9 . COOH. 



Later oxidation readily removes the COOH group, leaving acet- 
one CH 3 . CO . CH 3 (p. 413). 

Test. — Having acidulated 50 c.c. of urine with sulphuric acid, 
it is shaken with an equal volume of ether. The ether separated 
is shaken with a small quantity of dilute solution of ferric chlorid. 
A red or violet color in the reagent indicates aceto-acetic acid. 

Fallacy. — Antipyrin, salicylate, and other synthetic aromatic 
drugs give a blue-red or purple color to ferric chlorid, but the 
color is deepened by warming, whereas the diacetic-acid red ether 
disappears or is greatly lessened (Plate 8, Fig. 6). 



FATS AND FATTY OILS 

Tallow is the solid fat obtained from beef and mutton suet by 
expression when kneaded in a muslin bag under hot water. Lard 
is hog fat treated by a similar process. Fatty oils are obtained 
by pressing the seeds or fruits of cotton, olive, linseed, and palm. 
When treated with superheated steam all of them absorb water and 
break up into glycerin (glycerol) and the acids, oleic, palmitic, 
and stearic. Distilled in the hot steam, these pass over and are 
collected in the receiver with the acids in a semisolid mass, floating 
on the dilute glycerin. 

Fat + water at 200 ° C. = glycerin + acid. 

To express the movement of the atoms the following equation 
is used, the fat being tristearin: 



FATS AND FATTY OILS 427 

CH 2 .O.OC.C 17 H 35 CH 2 .OH HO.OC.C^H* 

CH.O.OC.C 17 H 35 + 3 H 2 = CH.OH + HO.OC.C,^ 
CH 2 .O.OC.C 17 H S5 CH 2 .OH HO.OC.C 17 H 35 . 

Tristearin Glycerin Stearic acid 

(1 molecule) (1 molecule). (3 molecules). 

Glycerin has already been described as a tri-acid base, under 
the class of Trihydric Alcohols (p. 401); its formula is C 3 H 5 (OH) 3 , 
or glyceryl trihydroxid. The fats are sometimes called glycerids, 
glycerin esters, or ethereal salts. They are named after the acids 
forming them, as tripalmitin (or glyceryl tripalmitate), tristearin, 
and triolein. The firm solid fats, such as tallow, get their hardness 
at ordinary temperatures from their large proportion of tristearin 
and tripalmitin. Those that are soft, like lard, have a large pro- 
portion of olein, and the liquid oils are composed chiefly of that 
element. 

Saponification. — The fats decompose more readily by the 
action of alkalis than by hot water alone. The acids leave the 
weak base glycerin to join the alkali metals, forming soaps. A 
soap then is a salt containing an alkali metal united with oleic, 
palmitic, or stearic acids. They remain dissolved in water until 
common salt is added to make them insoluble, when the curds of 
soap rise to the surface. The glycerin is left dissolved in the liquid 
with the mineral salt. 

/O.C 18 H 35 /OH 

C 3 H 5 ^O.C 18 H 35 + 3KOH = CH 6 A)H + SKOC^H^O. 
\O.C 18 H 35 \OH 

Glyceryl stearate (stearin). Glycerin. Potassium stearate 

(soft soap). 

When sodium replaces the hydrogen of stearic, palmitic, and 
oleic acids the product is hard soap (sapo, U. S. P.)- If potassium 
be the alkaline metal, then sojt soap (sapo mollis, U. S. P.) is the 
product. 

From this first process of splitting up a fatty ester of glycerin 
with a metallic hydroxid the term saponification was extended 
to the decomposition of esters by alkalis, even when the product was 
not a soap. Thus: 

(C,H 5 ) 2 S0 4 + 2KOH = 2C 2 H 5 OH + K 2 S0 4 . 

Ethyl sulphate. Alcohol. 

Experiment 1. — Make a solution of potassium hydroxid, 10 gm., 
in 100 c.c. of water and put in a beaker with 25 gm. of tallow. 
Boil and stir about half an hour until oil globules disappear from 
the surface. The homogeneous liquid is a mixture of glycerin, 
soap, and potassium hydroxid. Add a solution of 15 gm. of 
sodium chlorid in 75 c.c. of water and boil again. The soft 
potash soap changes to hard sodium soap, which separates and 
floats on the briny liquid. 



428 ALIPHATIC COMPOUNDS 

Experiment 2. — Skin off the sodium soap or use a piece of ordi- 
nary soap; dissolve in water, with the aid of alcohol. Add solution 
of calcium chlorid; a white precipitate of insoluble lime soap 
separates. 

Hydrolysis is a term for the analogous decomposition when 
water is absorbed and not the alkaline hydroxid. It implies that 
the breaking up of one compound into two or more is consummated 
by the participation in the process of the elements of water as in the 
splitting of fats by superheated steam (p. 402). Thus: 

C 2 H 5 . C 2 H 3 2 + H 2 = C 2 H 4 2 + C 2 H 5 OH 

Ethyl acetate. Acetic acid. Alcohol. 

Hydrolysis may be brought about by an enzym of the pan- 
creatic juice known as steapsin. The process is sometimes 
referred to as hydrolytic cleavage. 

Experiment 3. — Put in a test-tube 5 c.c. of oil and a few drops 
of oleic acid, add 10 drops of a strong solution of sodium carbonate 
and shake well. The sodium and the free acid unite to make 
a soap which envelops the fat globules so that they do not coalesce, 
but make a permanent emulsion. 

Butter. — The butter-fat of milk is a complex mixture of glycerids, 
characterized by a relatively larger amount of lower volatile fatty 
acids. When decomposed by hydrolysis it yields about 95 per 
cent, of fatty acids, 85 to 90 per cent, of which are the non-volatile, 
insoluble, higher acids — stearic, palmitic, oleic, myristic — and the 
remainder, 5 to 10, is made up of the volatile, soluble acids — 
butyric, caproic, caprylic, and capric. No other fat yields so large 
a percentage of volatile acids when distilled with water. 

Oleomargarin is an imitation of butter in color, odor, and 
taste. It is manufactured from beef suet. The beef fat is minced 
fine, heated by steam, and at a certain temperature put under 
pressure. A yellow oil (oleo oil) exudes and solid stearin remains. 
The oleo oil is churned with milk to get the butter flavor and 
colored with artificial butter yellow. When the process is care- 
fully conducted a product is obtained which may not be so easily 
digested as butter, but which is wholesome and nutritious. But- 
terin and suin are of similar manufacture, using the fat not only 
of beef, but also of mutton; and sometimes they contain lard and 
cotton-seed oil. 

Properties of Fats. — When pure, the fats are without odor 
or color, leave a greasy stain on paper, are lighter than water, 
with which they do not mix. They are soluble in ether, chloroform, 
carbon disulphid, benzol alcohol, etc. When the solid fats are 
dissolved in ether or chloroform and evaporated on the slide of a 
microscope, characteristic crystals are seen. As found in nature. 



FATS AND FATTY OILS 429 

they have taste, odor, and color, due to more or less impurity. 
On standing they become rancid — that is, they acquire an un- 
pleasant smell and taste and an acid reaction. This is due to the 
action of oxidizing ferments, which in the case of butter may be 
prevented or retarded by the admixture of antiferments, such as 
boric acid. Rancidity is sometimes corrected and the butter 
" renovated" by heating with solution of sodium carbonate. 

Fats and fatty acids are extracted from other material by 
shaking with ether, which dissolves them, but not the mineral salts, 
proteids, or carbohydrates. A separating funnel lets the aqueous 
material run off first, retaining the ether. 

Tests. — 1. Fats are the only substances that are stained by the 
alcoholic solution of red Sudan III. 

2. Osmic acid, in i per cent, aqueous solution, stains olein 
black, but does not stain the other fats. Olein is always present 
in animal fats. 

Fats in the Body. — A certain percentage of fats is present 
in almost all our food-stuffs. They make up nearly all of the 
weight of olive oil, cream, butter, bacon, and the fatty tissue of 
ordinary meats. The fundus of the stomach secretes a lipase 
which can split emulsified fat of milk. They are not completely 
digested until they reach the small intestine, where they undergo 
hydrolytic cleavage (p. 428) by the action of a pancreatic enzym, 
steapsin, and another lipase of the bile into glycerin and the fatty 
acids. Some of the free acid unites with the sodium of the alkaline 
bile and intestinal juices to form a soap. 

This soap emulsifies the rest of the fat, hastening the action of 
the steapsin upon it, and promoting its absorption. It is a growing 
opinion that the fat is all split first and passes into the intestinal 
cells in solution as soap, glycerin, and free acid, which during 
transmission are recombined into molecular fat by the cells, 
reversing the reaction and splitting off the sodium. Some of the 
stored fat of adipose tissue in the body is derived from sugar and 
some from proteid substances, beside what may be obtained from 
fatty foods. Most of the fat of food is oxidized to C0 2 and H 2 
in the tissue cells as fast as it comes to them, affording molecular 
and chemical energy and maintaining the normal temperature. 
Being rich in carbon, fat is very combustible and liberates a large 
amount of heat. The stored fat is a reserve of potential energy 
brought into use in wasting diseases attended by failure of nutrition. 

Waxes. — The class of which beeswax is a member does not 
have glycerin as a component. It includes the esters of mona- 
tomic alcohols, such as melissyls up to C 30 united with higher fatty 
acids up to C 18 . 



43 O ALIPHATIC COMPOUNDS 

ESTERS 

COMPOUND ETHERS, ETHEREAL SALTS 

In the presence of acids the alcohols behave like metallic hy- 
droxids and form compounds resembling mineral salts, with 
water as a by-product. These are sometimes called ethereal salts, 
but a better name is esters, as they do not dissociate, after the 
manner of true salts. Mention has been made of the first reaction 
between sulphuric acid and alcohol, producing ethyl hydrogen 
sulphate, C 2 H 5 HS0 4 , and water (p. 404), the intermediate products 
in the conversion of alcohol into ether. This compound, also 
called ethyl sulphuric acid and sulphovinic acid, has an acid 
reaction and acts like a monobasic acid, since it retains one atom 

of replaceable hydrogen. The formula, S0 2 <qtt 2 5 ' is typic of 

a class known as ethereal sulphuric acids, in which the radical (R) 
is linked to the sulphur by an oxygen atom, while in sulphonic acids 
the radical is directly united to the sulphur atom. This difference 
of constitution is indicated as follows: 

OwOR OwR 

0/ b \OH 0/\OH 

Ethereal sulphuric acid. Sulphonic acid. 

For the hydrogen of the —OH, metals and bases can be sub- 
stituted, thus constituting a large class known as ethereal sulphates, 

OP TT 

as sodium ethyl sulphate, S0 2 <C nN - 2 5 ' 

It is the characteristic of sulphanion, (S0 4 )", to form with 
barium, Ba", an insoluble BaS0 4 . As ethyl sulphuric acid forms 
no precipitate with barium chlorid, its dissociation must be into 
the hydrogen cation and a complex anion, thus: H* (C 2 H 5 S0 4 )'. 
In order to precipitate an ethereal sulphate with barium chlorid 
this complex anion is first broken up by boiling with hydrochloric 
acid to liberate (S0 4 )" (p. 588). 

Ethyl Nitrate (C 2 H 5 .NO) (Nitric Ether).— Owing to the 
heat evolved and explosive violence of the reaction, it is not pru- 
dent to make this compound by the direct action of concentrated 
nitric acid upon alcohol. When urea is present to decompose the 
nitrous acid formed, the operation is much less violent and the 
distilled product is ethyl nitrate. 

It is a colorless, volatile liquid, with an agreeable fruity odor. 

Ethyl nitrite (C 2 H 5 . N0 2 ) (nitrous ether) can be prepared by 
the action of nitrous acid on alcohol: 

C 2 H 5 OH + HN0 2 = C 2 H 5 .N0 2 + H 2 0. 



ESTERS 43 1 

This is a colorless, volatile liquid, with an odor like that of apples. 
When 4 per cent, is mixed with alcohol it is employed in medicine 
as sweet spirits oj niter, spiritus cetheris nitrosi. 

Amyl nitrite (C 5 H n . N0 2 ) (amylis nitris), prepared by the 
action of nitrous fumes on amyl alcohol. It is a yellowish volatile 
liquid, with a peculiar fruity and suffocative odor. It is insoluble 
in water. The 8o-per cent, alcoholic solution is used in medicine. 
Its vapor explodes when heated to 95 ° C. (203 ° F.). 

Toxicology. — When inhaled it dilates the arteries, causing 
flushing of the face and a sense of fulness about the head. It 
relieves cardiac tension and the painful feelings of angina pectoris. 
In poisonous doses it produces weakness, nausea, vomiting, 
thready pulse, stupor, and collapse with cyanosis. 

The antidotes are strychnin hypodermically, and digitalis. 
When swallowed it may be detected in the gastric contents by 
distillation, carefully protecting the distillate from evaporation. 
By agitation of the aqueous distillate with ether it may be sep- 
arated. By heating with potassium hydroxid the amyl nitrite 
forms amyl alcohol and potassium nitrite. The latter may be 
identified by theY tests *f«r nitrites. 

Nitroglycerin , (C 3 H 5 (N0 3 ) 3 ) (glyceryl trinitrate, trinitrin, 
glonoin) is an ester of nitric acid and glycerin. It is prepared 
by gradually mixing glycerin with sulphuric and nitric acids. 
The product is a heavy oil, which is washed thoroughly with 
water and dried. 

Properties. — It is a pale yellow oil of specific gravity of 1.6, 
with a sweet taste, insoluble in water, soluble in ether, and spar- 
ingly soluble in alcohol. It ignites with difficulty by a flame in 
an open vessel, but when suddenly heated to 250 C. (482 ° F.) 
it explodes. Its most remarkable property is that of exploding 
with violent energy on percussion. The complex molecule con- 
taining combustible elements in intimate association with oxygen 
instantly breaks up into a large volume of mixed gases, C0 2 , H 2 0, 
and free N. To make it safer when handled the nitroglycerin 
is absorbed into an inert infusorial earth, and is then called 
dynamite. This does not explode by pressure or by a simple 
jar. 

When mixed with guncotton (nitrocellulose) it is employed as 
blasting gelatin. It enters into the composition of certain forms 
of smokeless powders. 

Medical Uses. — When inhaled nitroglycerin causes aching and 
a sense of fulness with throbbing in the head. Its effects on 
heart diseases are like those of amyl nitrite, only intensified and 
more persistent. By relaxing the peripheral vessels it relieves 
the high blood-pressure and spasmodic pain of angina pectoris. 



432 ALIPHATIC COMPOUNDS 

Spiritus glycerylis nitratis is a i-per cent, alcoholic solution. 
Dose: i to 2 min. 

Toxicology of Nitroglycerin. — Powder headache is a symptom 
frequently seen in persons employed in the manufacture of the 
high explosives containing nitroglycerin. One drop applied to 
the unbroken skin may cause prolonged headache. Criminals 
give it in whisky to " knock out" the victim. 

Symptoms. — Severe headache is constantly present, with gid- 
diness, fulness of the arteries, throbbing of the temples, and mus- 
cular weakness. Marked distress is caused by vomiting, diarrhea, 
and griping pains. The breathing is hurried and difficult; cyanosis 
and coma soon appear. Habitual exposure and dosing soon induce 
tolerance. 

Fatal Dose. — A few drops of the undilute nitroglycerin would 
probably be fatal. Death does not usually occur for several 
hours, even after large doses. 

Treatment. — The stomach and bowels should be promptly 
washed out or evacuated. The symptoms should be treated as 
they arise. 

Postmortem Appearances. — The alimentary tract shows con- 
gestion, due to local irritation; the brain and meninges are hyper- 
emic. 

Detection. — Nitroglycerin rapidly decomposes after absorp- 
tion. It must be sought in the vomited matters and contents of 
the stomach. These are to be shaken out with chloroform or 
ether. The extract evaporated leaves a residuum of fat and 
nitroglycerin. Cold alcohol dissolves the nitroglycerin, leaving 
the fat, and evaporation of the alcohol gives us the material to 
test. 

Tests. — (1) Heated in a capillary tube nitroglycerin explodes. 
(2) Like all nitrates and nitrites it develops a crimson color 
when treated with brucin and a drop of concentrated sulphuric 
acid. 

ESTERS OF ORGANIC ACIDS 

These resemble one another more closely than do the esters of 
the diverse mineral acids. They are formed to some extent when 
an alcohol is treated by an organic acid, such as formic, acetic, 
or butyric. The process is soon arrested, as the water formed 
hydrolyzes the ethereal salt, reconverting it into ester, acid, and 
alcohol, an equilibrium resulting. To remove the water the 
complete process requires that so'me dehydrating agent, such as 
sulphuric or hydrochloric acid, should be present. 

When an ester such as ethyl acetate is added to water the 
process is reversed. Alcohol and acetic acid are formed until 
all four are present in a certain degree of concentration, which is 



CARBOHYDRATES ' 433 

maintained until a dehydrating agent, such as sulphuric acid, is 
added. This breaks up the phases of the system in equilibrium 
by removing the component water. The double arrows of the 
following equation mean that the movements are opposite in direc- 
tion and equal in velocity (p. 83). 

Alcohol + Acetic acid ^^ Ethyl acetate -f- Water. 

Ethyl Acetate (C 2 H 5 . C 2 H 3 2 ) (Acetic Ether).— This is pre- 
pared by mixing alcohol, acetic acid, and strong sulphuric acid, 
and distilling by heat. The distillate is shaken with a strong 
solution of common salt, to take up the alcohol, and the ethyl 
acetate rises to the top as a colorless, mobile, oily-looking fluid. 
It has a pleasant fruit-like smell, and is moderately soluble in water. 
The fine bouquet of hock wine is due mainly to the small amount 
of ethyl acetate it contains. 

This is a type of the class of ethereal salts which are found 
naturally in fruits and flowers, giving to them, by varied Mend- 
ings, the scent and flavor. Artificial jruit essences are prepared 
after processes like that given above for ethyl acetate, and largely 
sold to flavor ices, syrups, candies, and pastries. Pear oil is amyl 
acetate, pineapple oil is methyl butyrate, wintergreen oil is methyl 
salicylate. 



CARBOHYDRATES 



The term carbohydrate is applied to substances composed of 
carbon, hydrogen, and oxygen, the two latter being in the ratio 
to form water. The carbon atoms are in an open chain. In this 
group will be found the most important solid constituents of 
plants suitable for human food — sugars, starches, gums, and 
cellulose. 

For good reasons substances have been admitted to the group 
which are known to contain hydrogen and oxygen in a ratio 
different from H 2 0. 

The termination -ose is used to denote membership in the car- 
bohydrates; thus, dextrose, levulose, amylose. 

Properties. — Most of the carbohydrates are fermentable them- 
selves, or easily change to fermentable compounds. They are 
usually neutral, white, non-volatile, odorless solids, and in solution 
turn a polarized ray of light from the direct path. The sugars are 
sweet, reduce metallic oxids, and change by oxidation to sac- 
charic, mucic, or oxalic acids. 

Classification. — The modern division of carbohydrates is 
into simple sugars, compound sugars, and starches, or: 
28 



434 ALIPHATIC COMPOUNDS 

Monosaccharids (monoses or simple sugars), which cannot be 
made to yield other sugars by the action of dilute acids (glucose, 
levulose, pentose, galactose, etc.). About 12 simple sugars occur 
in nature, all of which, and in addition 40 others, purely artificial, 
have been made by synthesis in the laboratory. 

Disaccharids (saccharobioses), which, by boiling with dilute 
acids, can be made to take up 1 molecule of water and split up 
into 2 simple sugar molecules (saccharose, maltose, lactose, etc.). 

Polysaccharids, which are not sugars, but by the hydrolytic 
action of boiling dilute acids take up 2 or more molecules of water 
and yield a number of simple sugar molecules (starches, gums, 
cellulose, etc.). 

MONOSACCHARIDS 

The structure of the monosaccharids has been determined as 
that of mixed compounds, which are either alcohols and aldehyds 
(aldoses), or alcohols and ketones (ketoses). The aldoses contain 
the alcohol group, CH 2 OH, and the aldehyd group, COH; the 
ketoses have the same alcohol group and the ketone group CO, 
linking 2 radicals. 

The monosaccharids are called, according to the number of 
carbon atoms they contain, trioses, C 3 H 6 3 ; tetroses, C 4 H 8 4 ; 
pentoses, C 5 H 10 O 5 ; hexoses, etc., up to nonoses, C 9 H 18 9 , which 
have 9 carbon atoms. Only those containing 3 carbon atoms or 
a multiple of three (trioses, hexoses, nonoses) are capable of 
alcoholic fermentation or of assimilation by digestive processes. 
They are neutral, white, sweet, odorless compounds, soluble in 
water and sparingly so in alcohol. They share with aldehyds and 
ketones, containing a number of alcoholic groups, a reducing 
power on metallic oxids; hence give the familiar reaction of reduc- 
tion shown by Fehling's, Boettger's, and Nylander's tests (p. 602). 
Minute traces of any sugar are detected by Molisch's test (p. 473), 
in which a violet color is developed when the carbohydrate is 
mixed with a small amount of alpha-naphthol and sulphuric acid. 
This is due to a combination of alpha-naphthol with the fur- 
furaldehyd formed by the action of sulphuric acid on the sugar. 
Their solutions acidulated with acetic acid and heated with phenyl- 
hydrazin all give yellow crystalline precipitates, called osazones 
(Plate 3). This last reaction separates the sugars from aldehyds, 
ketones, and all other substances. While all are interesting, 
chemically, to the physician, only the hexoses and pentoses have 
any importance. 

The hexoses, C H 12 O 6 , include dextrose, levulose, and galac- 
tose. Dextrose (glucose) is called also grape sugar, because it is 
abundant in grapes and forms the brownish warty masses on 



MONOSACCHARIDS 435 

raisins. Mixed with levulose (fructose) it is widely distributed in 
the sweet juices of fruits and in honey. Human blood and urine 
in their normal condition may contain traces, but not more than 
o.i per cent., revealed by very delicate tests. In diabetes mellitus 
the proportion rises sometimes higher than 5 per cent., and then, 
constitutes the chief phenomenon of disease. 

Preparation. — When a solution of starch or other polysac- 
charid is acidulated with sulphuric or some other mineral, acid 
and boiled, the starch is hydrolyzed and splits up, forming, when 
dry, the commercial grape-sugar, of which 60 per cent, is true 
glucose. Sometimes the product is not evaporated to dryness, 
and is a thick, colorless syrup, commercial glucose, which con- 
tains, besides sugar, some dextrins and nitrogenous bodies. 

From both of these products the sulphuric acid is removed in 
the manufacture by neutralizing with calcium carbonate, which 
precipitates calcium sulphate. As commercial sulphuric acid 
often contains traces of arsenic and lead, it is not surprising that 
glucose made by its aid sometimes causes slow poisoning. Wide- 
spread epidemics have resulted from brewing beer with such 
a glucose (p. 288). 

Sulphurous acid is sometimes used to decolorize the syrup, and 
sulphates may be left in it as a contaminant. These are active 
antiferments, injurious to the digestion. 

Properties. — Dextrose, C 6 H 12 6 , is an aldose — that is, it has 
the behavior of an aldehyd and also of a polyhydric, alcohol. 
From a sufficient number of experimental data its constitution 
has been worked out to be CH 2 OH . (CHOH) 4 . COH. 

The ordinary syrup of the grocers is commonly liquid glucose 
made from starch, decidedly less sweet than the syrups made 
from cane-sugar. Dextrose by evaporation may be obtained as 
hard anhydrous crystals, or another sort with 1 molecule of water 
of crystallization. It is less soluble and less sweet than cane- 
sugar, and, unlike that substance, is not charred when warmed 
with sulphuric acid. Its aqueous solutions placed in the polar- 
izing apparatus are dextrogyrous (hence the name dextrose) — 
that is, they turn the ray of polarized light toward the right hand, 

Wd=+52-5° (P- 61). 

Dextrose, like the aldehyds, is an active reducing agent, pre- 
cipitating the metal from warm solutions of the salts of silver, 
gold, and platinum. Its reduction tests (Fehling's, etc.) are 
given in detail in another place (p. 602). With brewer's yeast its 
dilute aqueous solutions readily ferment at ordinary temperatures, 
according to the equation: 

C 6 H 12 6 = 2C 2 H O + 2C0 2 . 

Glucose. Alcohol. 



436 ALIPHATIC COMPOUNDS 

In addition to the principal products, ethyl alcohol and car- 
bon dioxid, a trace of amyl alcohol is formed and some glycerin 
and succinic acid. A weak solution made feebly alkaline and 
exposed to direct sunlight yields the same products, thereby 
showing a natural tendency to break up this way, which the zymase 
of yeast accelerates. With phenylhydrazin acetate and gentle heat 
it forms fine crystals of phenylglucosazone, which fuse at 205 ° C. 
(401 ° F.) (Plate 3, a). 

When oxidized with bromin water, dextrose, CH 2 OH(CHOH) 4 - 
COH, is changed to monobasic gluconic acid, CH 2 OH(CHOH) 4 - 
COOH. More powerful oxidizers, such as nitric acid, produce 
dibasic saccharic acid, COOH(CHOH) 4 COOH, the last oxida- 
tion derivative of dextrose being oxalic acid. In the body the COH 
group of glucose is not oxidized first to gluconic acid, but the 
CH 2 OH group is oxidized, making glycuronic acid. In the 
laboratory, by reduction of saccharic acid, the first product is 
glycuronic acid, COOH. (CHOH) 4 COH, a normal constituent of 
the body which is eliminated in appreciable amounts by the urine 
after full doses of chloral, camphor, and other similar substances. 
As it responds to the copper and other reduction tests like glucose, 
it is the source of a fallacy in testing the urine for that substance. 
Glycuronic acid does not ferment with yeast nor form glucosazone 
with phenylhydrazin acetate. The free acid is dextro-rotatory, 
but its usual compounds, the conjugate glycuronates, are levo- 
rotatory. 

Levulose (C 6 H 12 6 ) (Fructose, Fruit-sugar). — This is the 
portion of the sweet juices of fruits and of honey which does not 
crystallize; or does so with great difficulty. In composition it is 
a ketose, its constitutional formula being CH 2 OH(CHOH) 3 CO .- 
CH 2 OH. It is obtained, with an equal quantity of dextrose, 
when cane-sugar is inverted by hydrolysis with dilute mineral 
acids: 

C12H22O11 + H 2 = C 6 H 12 6 + C 6 H 12 6 

Cane-sugar. Dextrose. Levulose. 

Its name is derived from its levorotatory property, turning the 
polarized ray strongly to the left, as shown by its equation, [a]p = 
— 93° (P- 61). As this is a greater angle than that of dextrose, 
inverted sugar is slightly levorotatory. An explanation of the 
optical difference is found in the stereochemical formulas of 
dextrose and levulose. Dextrose is the aldehyd of the alcohol 
sorbite, or CH 2 OH(CHOH) 4 COH. Levulose is the ketone of 
the alcohol mannite or CH 2 OH(CHOH) 3 CO . CH 2 OH which 
shows it to have the ketone group CO and in addition alcohol 
groups at both ends. By oxidation it readily yields acids and 



MOXOSACCHARIDS 43 7 

ultimately oxalic acid. Like dextrose, it reduces Fehling's solu- 
tion, by virtue of two alcohol groups, and forms glucosazone with 
phenylhydrazin. It is less fermentable than dextrose. It may 
be recognized by the following reaction: Heated with a little of 
a weak solution of resorcin in 20 per cent, hydrochloric acid, it 
forms a red color and precipitate. 

Both dextrose and levulose have been made by synthesis from 
formaldehyd. By adding milk of lime to an aqueous solution of 
formaldehyd jormose is obtained. Formose is a mixture of dif- 
ferent sugars of the formula C 6 H 12 6 , apparently polymerized 
formaldehyd: 

6CH 2 = C 6 H 12 6 

Formaldehyd. Glucose. 

The mixture can be made to yield both dextrose and levulose. 

Galactose, C 6 H 12 6 or CH 2 OH(CHOH) 4 COH, is formed by 
the hydrolysis of milk-sugar, and also by boiling certain gums with 
dilute sulphuric acid. It crystallizes in prisms, reduces copper 
solutions, is strongly dextrorotatory, and ferments with yeast. 
Oxidized with nitric acid, it yields mucic acid. 

Inosite (C 6 H 12 6 ) {muscle-sugar) occurs in beans and peas, the 
liquid of muscular tissue, and in various organs of the body. 
Traces are found in normal urine, the amount increasing in dia- 
betes and in some cases of Bright's disease. Although mentioned 
in this place among the carbohydrates because of its sweet taste, 
its true composition is hexahydroxy-benzol, C 6 H 5 (HO) 6 . It does 
not reduce Fehling's solution nor ferment with yeast, but under- 
goes the lactic and butyric fermentations. 

The Pentoses (C 5 H 10 O 5 ). — All the pentoses yet studied are 
aldoses with the constitutional formula CH 2 OH(CHOH) 3 COH. 
Arabinose is a product of the action of dilute sulphuric acid on 
cherry gum; xylose {wood-sugar) is obtained in the same way 
from wood, gum, and straw. Other polysaccharids than gum, 
such as the pentosanes of pears, are hydrolyzed by acids or by 
digestion in the body into pentoses. They are distinguished from 
ordinary sugars by the large amount of furfuraldehyd yielded 
when they are distilled with hydrochloric acid. The human 
urine, after ingestion of certain foods containing pentosanes, 
prunes, cherries, grapes, and beer, and also in certain persons as 
an anomaly in their metabolism, contains pentose, and this may 
constitute a fallacy in testing for glucose in supposed diabetics. 
Pentoses respond to Fehling's test, form osazones with phenyl- 
hydrazin, but are not fermentable with yeast. They develop a 
green color when heated with a saturated solution of orcin in 
hydrochloric acid (p. 606). 



438 ALIPHATIC COMPOUNDS 

DISACCHARIDS 

The empiric formula for this group in general is C 12 H 22 O u . 
Facts are lacking from which to establish with confidence the 
constitutional formulas of the different members. They appear 
to contain 2 molecules of monosaccharids, less the constituents 
of water, for by hydrolysis with dilute mineral acids they may all 
be resolved into 2 hexose molecules. Thus: 

C12H22O11 + H 2 = 2 C 6 H 12 6 . 

Taking up H 2 0, cane-sugar becomes the hexoses, dextrose, and 
levulose; milk-sugar is converted into dextrose and galactose; 
maltose into 2 molecules of dextrose. A convenient division is 
made between those which do not reduce Fehling's solution (cane- 
sugar) and those which, like the hexoses, possess this power 
(lactose and maltose). 

Cane=SUgar, saccharum, U. S. P. (C 12 H 22 O n ) (saccharose, 
sucrose), exists widely distributed in the sugar-cane, sorghum, 
beet root, sugar maple, and in smaller amounts in pineapples, 
sweet berries, and other fruits. The expressed juice is freed from 
vegetable albumin, decolorized, evaporated until it begins to 
deposit crystals, and then in a centrifuge the crystals of sugar are 
separated from the mother-liquor. The brown mother-liquor, 
called molasses or treacle, contains 50 per cent, of sugar that does 
not crystallize until various impurities are removed. 

The crystals are hard four-sided prisms, soluble in one-third 
their weight of water, but slightly in alcohol. Rock candy is 
cane-sugar crystallized' slowly and without agitation from con- 
centrated solutions. Beet-sugar differs from cane-sugar only in 
being lighter in equal volumes. Cane-sugar melts at 160 C. 
(320 F.), and on cooling the liquid solidifies to a yellow, glassy, 
amorphous mass called barley-sugar. Heated to a higher tem- 
perature, it is decomposed into glucose and levulose. At 200 ° C. 
(392 ° F.) it loses water, and is converted into a brown mass called 
caramel or burnt sugar, used to color liquors and soups. Cane- 
sugar carbonizes when treated with warm concentrated sulphuric 
acid, in this respect differing from glucose. 

The action of its aqueous solutions upon polarized light is 
the basis of a method of determining the degree of concentration. 
The polarizer used for this purpose is called a saccharimeter, 
and shows the deflection to the right, according to the formula 
Mz>=+66.5° (p. 61). 

After being hydrolyzed by boiling with acids the levulose 
product twists the ray in the reverse direction and the invert- 
sugar becomes levorotatory to a slight degree. 



DISACCHARIDS 



439 



Cane-sugar is the only sugar that has no action on Fehling's 
solution, though it reduces potassium permanganate. Yeast does 
not excite alcoholic fermentation in it directly, but after some time 
a secondary ferment of the yeast, invertase, develops from it 
dextrose and levulose, and these are fermentable. With phenyl- 
hydrazin it does not yield an osazone, differing in this respect 
from all the other sugars. With the hydroxids of strontium, 
calcium, and barium it combines to form compounds called 
saccharosates or sucrates. The compound with calcium is used 
in medicine under the name of saccharate of lime. 

As it does not ferment readily, strong cane-syrups are used as 
preservatives of canned fruit. In the body an inverting enzym 
for cane-sugar occurs in the pancreatic and intestinal juices, 
which forms glucose more readily from maltose than from cane- 
sugar. 

Maltose, C 12 H 22 O n , with dextrin is produced from starch by 
the action of the ferment diastase in malted or germinated grain: 

3(C 6 H 10 O 5 ) n + nU 2 = »C 12 H 22 O u + «C 6 H 10 O 5 

Starch. Maltose. Dextrin. 

This hydrolysis is accomplished to a limited extent by the 
action of dilute sulphuric acid upon cornstarch, as in the process 
for manufacturing commercial glucose. Ultimately it is com- 
pletely converted into dextrose, showing that it is an anhydrid of 
that substance. It crystallizes with water in needles, is very 
soluble, is strongly dextrorotatory [a] D = + 140.6 °, ferments 
readily with yeast, and reduces Fehling's solution. It forms an 
osazone with phenylhydrazin (Plate 3, b). If the enzym maltase 
is added to 20-per cent, maltose it changes only 86 per cent, to 
glucose; the equilibrium is reached with 14 per cent, of maltose 
left. This operation is reversed when the same enzym is added 
to 40-per cent, pure glucose. It builds up maltose until 14 per 
cent, is made, when the action ceases (Fig. 30). 

Milk=SUgar, saccharum lactis, U. S. P. (C 12 H 22 O u , (lactose), is 
found in the milk of mammalia in the average proportion of 4 
per cent. After the removal of butter, fat, and casein in the 
manufacture of cheese, the remaining liquid yields, on evaporation, 
white and extremely hard crystals of lactose. Compared with 
cane-sugar it is less soluble and less sweet. While it reduces 
Fehling's solution, the process is much slower than when glucose 
is present. It rotates the polarized ray to the right, [a] D = 
+ 5 2 -53° (P- 61). With yeast it does not ferment directly as 
glucose does, but changes very slowly into alcohol and lactic acid. 
When this change occurs in mare's milk, kumyss is the product; 



44Q 



ALIPHATIC COMPOUNDS 



from cows' milk kephir is obtained. By boiling with dilute acids 
milk-sugar is hydrolyzed and breaks up into dextrose and galactose: 



^12^22^11 

Lactose. 



+ 



H 2 



^6^12^6 

Dextrose. 



C 6 H 12 ( 

Galactose. 



With nitric acid it is oxidized to mucic acid (Plate 3, c). 

POLYSACCHARIDS 

These have the composition (C 6 H 10 O 5 ) n , but the constitution 
has not been ascertained. When hydrolyzed by acids they be- 
tray a much higher complexity than the disaccharids, splitting 
into monosaccharids, disaccharids, and dextrins. Thus, as 
stated on p. 439, starch is decomposed into maltose and dextrin, 
both of which have a very high molecular weight. The poly- 
saccharids are insoluble and non-crystallizable, both physical 
properties being generally associated with substances of a high 
molecular weight. 

Starch (C 6 H 10 O 5 ) n (amylum, U. S. P.) is found widely dis- 
tributed in almost all the tissues of plants, but is most abundant 
in all kinds of grain and in nutritious tubers, such as the potato. 





Fig. 80.— Potato starch (Wolf). 



Fig. 81.— Wheat starch (Wolf). 



The sugar and gluten are converted into soluble forms by rubbing 
and steeping in warm water, leaving starch to deposit from the 
washings as an amorphous mass. When dried it is a white pow- 
der, tasteless, odorless, and insoluble in cold water, alcohol, and 
ether. The microscope shows starch to be composed of granules 
marked with concentric striations and a cellulose envelope (Figs. 
80 and 81). 

The granules from different plants may be identified by their 
characteristic size, shape, and structure. When boiled in water 
these granules swell and burst, and a homogeneous white paste 



POLYSACCHARIDS 44I 

or jelly is formed. Prolonged boiling causes the granidose of the 
cell to pass into solution, leaving the cell wall or cellulose sus- 
pended. 

Experiment i. — Stir starch in cold water in a test-tube, filter, 
and test the filtrate with iodin. It does not turn blue because the 
starch has not dissolved. 

Experiment 2. — Boil water in a test-tube and add a small quan- 
tity of cold starch and water. It forms a thin paste which, when 
cooled, turns blue with iodin (soluble starch or amylodextrin). 

To assimilate the starch of food it must first be hydrolyzed by 
dilute acids or ferments into the monosaccharids, like glucose. 
The stages of conversion can be noted by the application of cer- 
tain tests (Exps., p. 544). 

The solution of starch {amylodextrin) yields a characteristic 
brilliant blue color with iodin, which disappears on heating to 
reappear on cooling. In the next stage (maltodextrin and erythro- 
dextrin) iodin gives a red color. In the third stage {achr 0-0 dextrin) 
iodin gives no color. At last maltose and dextrose are formed 
and can be identified by Fehling's solution. In any sample of 
starch passing through these changes some portions of the inter- 
mediate products are present at all periods, as the process is con- 
tinuous until complete. 

A possible explanation of the progress of the transformation 
may be found in the hypothesis that the starch molecule has the 
great weight of 50 (C 12 H 20 O 10 ). Breaking into 5 molecules of 
10 (C 12 H 20 O 10 ), it becomes soluble; hydrolyzed in successive stages 
it forms the series of dextrins and, simultaneously, maltose with 
each series. Thus: 

io(C 12 H 20 O 10 ) + 8(H 2 0) = 2 (C 12 H 20 O 10 + 8(C 12 H 22 O n ) 

Soluble starch. Achroodextrin. Maltose. 

Dextrin (C 6 H 10 O 5 ) n {British Gum).— This is the general term 
applied to one or a mixture of isomeric substances obtained 
as transitional forms in the process of converting starch into dex- 
trose. Besides the methods given above, it can be prepared by 
heating dry starch to 175 ° C. (347 ° F.). 

In appearance and properties it resembles gum arabic. The 
commercial article is a yellowish amorphous powder, which in 
concentrated aqueous solution is mucilaginous and adhesive. 

Gums (arabin and bassorin) are translucent amorphous sub- 
stances found in many plants. In water the vegetable gums 
swell up and make mucilages. Boiled with dilute sulphuric acid 
they yield glucose. 

Glycogen (C 6 H 10 O 5 ) 10 (animal starch) is a polysaccharid not 
found in plants, but largely in the liver and other tissues and cells 



442 ALIPHATIC COMPOUNDS 

of animals. It is partly derived from glucose by losing the ele- 
ments of water (dehydration) — 

ioC 6 H 12 6 less ioH 2 = (C 6 H 10 O 5 ) 10 . 

Liver tissue minced and extracted with hot water yields it in an 
impure form. The albuminoid material may be precipitated by 
acetic acid and potassium iodohydrargyrate, and the filtrate, 
treated with alcohol, deposits the pure glycogen. A white amor- 
phous powder, without odor or taste; its aqueous solution rotates 
the polarized ray strongly to the right, [a] D = + 196.6 °. With 
iodin it gives a wine red color which disappears on heating, to 
reappear on cooling. It does not reduce Fehling's solution, but 
is converted to glucose by dilute acids on certain enzyms. Like 
starch, it does not dialyze, but unlike starch it is readily soluble in 
cold water. 

Cellulose (C 6 H 10 O 5 ) n (Vegetable Fiber).— In all plants the 
woody skeleton and cell membrane are composed mainly of this 
substance. It exists almost free from other matter in cotton, 
wool, linen, and hemp. Swedish filter paper is cellulose made 
pure by the bleaching and washing processes to which the raw 
fiber has been subjected. Though isomeric with starch, its 
molecular weight is much greater than that of starch. Its behavior 
denotes that 10 hydroxyl groups enter into its constitution. Insol- 
uble in water, alcohol, and ether, it dissolves in Schweitzer 's 
reagent (ammoniacal solution of cupric oxid). From this solution 
it is deposited by acids as a gelatinous mass which changes by 
drying to a grayish powder. 

Cellulose swells and is slowly dissolved by concentrated sul- 
phuric acid. This solution of wood fiber, diluted with water and 
boiled, yields dextrin and glucose. Though the cellulose itself 
is not digestible, it is thus transformable into valuable foods. 

In the intestines of man cellulose of vegetable food is only to 
a limited extent dissolved: most of it passes out with the feces. 
In the herbivora only a small fraction reappears in the feces, 
showing that under the action of bacteria or enzyms it undergoes 
a fermentation into soluble products that are absorbed. 

Parchment paper is prepared by dipping unsized paper for a 
few seconds in sulphuric acid diluted with an equal volume of 
water. It is next washed with water and dilute ammonia and 
dried. The paper is greatly toughened without losing its other 
properties. It is substituted for parchment, which it closely 
resembles. 

Guncotton (Pyroxylin). — Pure cotton wool treated with a 
mixture of nitric acid, 1 part, and sulphuric acid, 2 parts, washed 



POLYSACCHARIDS 443 

and dried, is converted into cellulose hexanitrate, C 12 H 14 (N0 3 ) 6 4 . 
This is sometimes called trinity ocellulose, C 6 H 7 2 (N0 3 ) 3 . This 
is the violently explosive guncotton, insoluble in a mixture of ether 
and alcohol. If the cotton be dipped for a few minutes only, less 
of the nitric group unites with it, the product being tetra- and 
^ew/a-nitrates. These dissolve in a mixture of alcohol and ether 
with the formation of collodion, U. S. P., a colorless syrupy liquid. 
By the evaporation of the solvent the collodion is deposited as 
a transparent, smooth, contractile film, used as a surgical dressing 
or as a basis for photographic sensitive films. 

Celluloid is pyroxylin mixed with camphor and coloring sub- 
stances, and shaped by pressure. It is made non-inflammable by 
adding sodium or ammonium phosphate. Elastic collodion {collo- 
dium flexile, U. S. P.) contains castor oil and turpentine to render 
the collodium less contractile and constringent. It is used as a 
protective covering for wounds and abrasions. Styptic collodion, 
U. S. P., is flexile collodium made astringent by the addition of 20- 
per cent, tannic acid. Cantharidal collodion, U. S. P., has enough 
of the tincture of cantharides to make it a blistering application. 

Glucosids are natural principles of plants which are hydro- 
lyzed by alkalis, mineral acids, or certain enzyms, with the pro- 
duction of a sugar and another substance not a carbohydrate. 
The sugars formed are pentoses, hexoses, or disaccharids. The 
other product is usually a derivative of the aromatic compound. 
Their constitution has not been fully established. The class 
includes amygdalin, convolvulin, digitalin, indican, helleborin, 
salicin, santonin, sinigrin, strophanthin, etc. Amygdalin (C 2 H 27 - 
NO n ) occurs in bitter almonds, cherry, laurel, etc.; it is hydro- 
lyzed by the enzym emulsin to dextrose, benzoic aldehyd, and 
hydrocyanic acid (p. 464). Myronic acid or sinigrin occurs in 
black mustard as potassium myronate (KC 10 H 18 NS 2 O 10 ) and is 
hydrolyzed by the ferment myrosin in cold water to dextrose, 
mustard oil, and potassium sulphate (p. 539). 

Phlorhizin is a glucosid in the bark of apple and pear trees 
which is hydrolyzed and split into dextrose and phloretin. When 
this drug is given it causes a transient glycosuria, with diminution 
of the normal amount of glucose in the blood. Its action is specific 
upon the kidneys; their soundness is tested by the degree of excre- 
tion of glucose after a dose of phlorhizin. 

Carbohydrates in the Body.— Uncooked starch, being enclosed 
in an insoluble envelop, is not attacked by the enzyms of diges- 
tion in the saliva, but passes unchanged as far as the intestine, 
where part of it is decomposed by the bacteria and part digested. 
When its granules are burst by cooking the starch is set free and 
made partly soluble. The enzyms of the saliva, ptyalin and 



444 ALIPHATIC COMPOUNDS 

maltase, cause hydrolytic cleavage into soluble starch, dextrin, and 
finally maltose (p. 441). These changes go on in the mouth and 
even in the fundus of the stomach for a considerable time until 
gastric acidity is pronounced, when the portion yet undigested 
passes into the intestine to meet a rapid and powerful enzym, 
amylopsin of the pancreatic juice, also the amylases of the intes- 
tinal juices and invertase, which cause hydrolytic cleavage in the 
remainder of the starch, forming maltose, one molecule of which 
is split by an enzym in the epithelial cells of the stomach and 
intestines during transmission, to form two molecules of dextrose. 

Cane-sugar is not altered by ptyalin nor by amylopsin, but 
before absorption is hydrolyzed to dextrose and levulose either 
in the stomach by the hydrochloric acid or in the intestines by 
the invertase or by the epithelial cells while passing through the 
walls. Lactose is hydrolyzed in the intestines, reaching the blood 
as dextrose. 

Fermentations by yeast and bacteria occur in a variable portion 
of the dextrose before absorption. These are typified in the 
following equations: 

1. C 6 H 12 6 =2C0 2 +2C 2 H 5 OH (alcohol). 

2. C 2 H 5 . OH+0 2 = H 2 + CH 3 . COOH (acetic acid). 

3. C 6 H 12 6 =2C 3 H 6 3 (lactic acid). 

4. 2C 3 H 6 3 =2C0 2 + 4H+C 3 H 7 . COOH (butyric acid). 

As the dextrose- in the portal vein passes through the liver, part 
of it is dehydrated to glycogen and is stored up; a large proportion 
passes the liver and is distributed throughout the body. 

In the muscles part is dehydrated and stored as glycogen and 
part is oxidized to lactic acid or to carbon dioxid and water, to 
give energy. Part of it is converted and stored as fat. It is 
probable that the carbohydrate excess stored in the liver as glyco- 
gen is rehydrated to glucose as it is needed by the body at large. 

An excess of glucose in the blood over its normal amount, 
0.1 to 0.2 per cent., is excreted at once by the kidneys, causing 
glycosuria. The kidneys do not form the sugar, but simply 
remove it. Among the cleavage products of protein metabolism 
are the sugars. The normal pancreas regulates this carbohy- 
drate and protein metabolism of other organs. When pancreatic 
disease arrests or perverts this influence, either more protein is 
converted to sugar or less sugar is used by the tissues. This 
causes excess of sugar in the blood and its separation by the kid- 
neys. The condition is known as pancreatic glycosuria. 



THE BENZENE OR AROMATIC SERIES 445 

CYCLIC COMPOUNDS 
THE BENZENE OR AROMATIC SERIES 

In the foregoing pages consideration has been given to the 
aliphatic compounds — that is, those of the paraffins, or the fatty 
series, and especially the derivatives of methane, CH 4 , as the first 
of two main divisions of organic substances. The other division 
is known as the cyclic compounds or those of the aromatic series, 
or the derivatives of benzene, C 6 H 6 . Many of the compounds 
belonging to the fatty series can be prepared directly from 
petroleum, or derived by synthesis from it; and so most of the 
aromatic compounds are obtained from coal-tar by fractional 
distillation and laboratory processes. 

As benzene is the lowest member, the whole group is called 
the benzene series, just as the other group is called the methane 
series. Certain compounds found in nature, such as benzoic acid, 
emit powerful odors, which are sometimes agreeable. Chemical 
studies having shown that these can be derived from benzene, 
which is itself aromatic, the term has been applied to the whole 
group. 

Coal=tar. — In the manufacture of coal-gas the coal is heated 
in closed retorts, the gas and other volatile products distilling out 
through a pipe, leaving solid coke behind. When the hot coal-gas 
is cooled, tar is one of the condensed substances, the coal-gas 
itself, after various washings, being collected in gasometers, from 
which it is distributed for lighting and heating purposes. The 
coal-tar is a thick black liquid, at one time treated as a refuse 
material. Modern chemistry has extracted from it a large number 
of organic compounds of the greatest medical and commercial 
value. The complex mixture of more than forty substances in the 
tar is subjected to fractional distillation at four temperatures, 
with the result that it is roughly separated into five fractions. 
By refining processes, (i) light oil, collected up to 170 C. (338 ° F.), 
yields the hydrocarbons benzene, toluene, and xylene; pyridin and 
other bases; carbolic and other acids. The (2) carbolic oil, col- 
lected between 170 C. and 230 ° C. (446 ° F.), consists principally 
of carbolic acid and naphthalene. That (3) collected between 
230 C. (446 F.) and 270 C. (518 F.), is used, under the name 
creosote oil, in treating wood for preservation. It contains cresol, 
carbolic acid, naphthalene, and anthracene. (4) Green oil, coming 
off above 270 C. (518 F.), contains anthracene and certain 
hydrocarbons solid at common temperature. The residue in 



446 CYCLIC COMPOUNDS 

the still (5) is pitch, employed hot as a varnish to protect wood 
and metal work. 

All of these bodies contain at least 6 atoms of "carbon, and 
the more complex aromatic compounds break up into simpler 
ones which contain at least 6 atoms. Through many changes 
the aromatic bodies retain the group of 6 carbon atoms, appar- 
ently joined to one another in such a way as to use up 18 of their 
combining powers, leaving 6 free. Of this class, the simplest 
and most important illustration is benzene, C 6 H 6 . From it all 
the compounds of this class may be derived by substituting for 1 
or more of the 6 hydrogen atoms those of other elements or more 
complex groups. These substances may be made in numerous 
cases to yield benzene when they are decomposed. In light oil, 
the first crude fraction distilled from coal-tar, are found 4 hydro- 
carbons, homologous with benzene; they are benzene, toluene, 
xylene, and cumene. From these, by synthetic process, the higher 
members and compounds are built up. In the following table 
they are arranged in the order of their molecular weight, according 
to the general formula, C n H 2n _ 6 . 



BENZENE HYDROCARBONS 

Benzene or Benzol, C 6 H 6 . 

Toluene or Toluol, C 7 H 8 , or Methyl -benzene C 6 H 5 CH 3 . 

Xylene or Xylol, C 8 H 10 , or Dimethyl-benzene C 6 H 4 (CH 3 ) 2 . 
Cumene or Cumol, C 9 H 12 , or Trimethyl -benzene C 6 H 3 (CH 3 ) 3 ; 
Tetramethyl -benzene C 6 H 2 (CH 3 ) 4 . 

Benzene (C 6 H 6 ). — Having removed carbolic acid from the 
oil of coal-tar by agitation with soda, and the bases by sul- 
phuric acid, distillation yields 90 per cent, benzol. By further 
fractional distillation and crystallization of the benzene in a 
freezing mixture, the commercial article is prepared. 

Pure benzene in small quantities is prepared by heating pure 
benzoic acid with soda-lime: 

C 6 H 5 .COOH = C 6 H 6 + C0 2 . 

Benzoic acid. 

Properties. — At common temperatures benzene is a colorless, 
mobile, volatile liquid of specific gravity of 0.880, boiling at 80.5 ° 
C. (176. 9 F.). Cooled to 5.4 C. (41. 7 F.) it crystallizes. It 
mixes with petroleum, alcohol, and ether, but not with water. 
It has an ethereal, pleasant smell; is highly inflammable, burning 



BENZENE HYDROCARBONS 447 

with the luminous, sooty flame indicative of richness in carbon. 
It is a ready solvent for iodin, fats, oils, and resins. Its chief use 
is in the manufacture of its derivatives, which are of great com- 
mercial importance. 

Toxicology. — A narcotic effect is produced by the accidental 
inhalation of benzene vapor in factories. One ounce (30 c.c.) 
taken by the stomach caused death after symptoms such as head- 
ache, giddiness, bluish flush of the face, delirium, convulsions, 
and coma. 

Constitution of Benzene. — Benzene behaves so differently 
from other hydrocarbons we have studied that its structure must 
be regarded as peculiar. Like the paraffins, it is extremely stable, 
decomposing with difficulty into simple compounds. Boiling 
alkalis do not affect it, and only very slowly is it oxidized by hot 
chromic acid. Chlorin and bromin at ordinary temperatures 
gradually attack the benzene molecule, forming by substitution 
chlorbenzene, C 6 H 5 C1; brombenzene, C 6 H 5 Br; dichlorbenzene, 
C 6 H 4 C1 2 ; dibrombenzene, C 6 H 4 Br 2 , etc. While nitric acid does 
not act on the paraffins, with benzene it forms nitrobenzene by 
substitution of the nitro radical, — N0 2 , for an atom of hydrogen: 

C 6 H 6 + HO.N0 2 = C 6 H 5 N0 2 + HO.H 

Benzene. Nitric acid. Nitrobenzene. Water. 

These substitutions are indications that C 6 H 6 is a saturated 
compound. It is not as fully saturated as methane, for in direct 
sunlight it forms with bromin additive compounds as high as hex- 
abromid, C 6 H 6 Br 6 , but never with more than 6 atoms. When 
studied very closely by elaborate experiments, it is evident that all 
the hydrogen atoms are alike in their relation to the carbon in the 
compound. Many facts combine to establish the following 
conclusions as their most reasonable explanation: 

1. The benzene molecide is symmetric. 

2. The 6 carbon atoms form a closed chain or hexagonal ring, 
called the benzene nucleus. 

3. Each carbon atom is directly united with only 1 atom of hy- 
drogen. 

The synthetic method of preparing benzene is by heating 
acetylene without air, when 3 molecules are converted into 1 
molecule of benzene by polymerization: 

3 C 2 H 2 = C C H 6 

Acetylene. Benzene. 

If we place the three molecules of C 2 H 2 side by side, thus: 



448 CYCLIC COMPOUNDS 

H 

I 

c 

H— C C— H 
H— C C— H 

C 

I 
H 

and suppose that each C atom turns a valence to its neighbor C 
atom, then the resulting molecule would be figured thus: 

H 



A 



/% 
H— C C— H 

II I 
H— C C— H 

\// 
C 

This graphic formula is used as a basis to represent all other 
facts ascertained concerning benzene and its derivatives, which 
are called cyclic because of this ring. When the ring contains 
6 carbon atoms it is called isocyclic; if less than 6 carbon atoms, 
then it is called heterocyclic. 

The entire theory of the constitution of organic compounds is 
based on the tetravalence of carbon. The above hexagonal ring 
shows 4 lines drawn from each carbon atom, 2 of the 4 lines 
meeting 2 other lines from the next carbon atom. Thus the car- 
bon atoms are linked by 1 or 2 valences alternately. The ability 
to form additive compounds is accounted for by the fact that each 
carbon atom has 1 affinity not actively engaged. By substitution 
or addition to this ring as a basis an infinite variety of molecules 
are constructed. For convenience in description the figure of 
a regular hexagon without letters is used to represent the entire 
benzene ring. Used alone, it stands for the whole molecule C 6 H 6 ; 
when other atoms or groups are* written at the angles they are 
understood as being substituted for an atom of hydrogen. Thus: 

COOH 







Benzene. Toluene. Nitrobenzene. Benzoic acid. 

C 6 H 6 C 6 H 5 (CH 3 ) C 6 H 6 (N0 2 ) C 8 H 5 (COOH) 



BENZENE HYDROCARBONS 449 

But One Monosubstitution Product. — With any monovalent 
element, such as bromin, or group, such as — N0 2 , there is formed 
by substitution but i monobenzene derivative. Thus, there is 
but 1 brombenzene, C 6 H 5 Br; 1 nitrobenzene, C 6 H 5 . N0 2 ; i ben- 
zoic acid, C 6 H 5 COOH, etc. The only possible conclusion is 
that the hydrogen atoms of C 6 H 6 do not differ in value. . 

Three Isomeric Bisubstitution Products. — With derivatives of 
benzene containing 2, 3, or 4 substituted monovalent elements or 
groups, there are 3 isomeric compounds, corresponding to the 
three possible differences in the relative positions of the radicals 
or groups. For example, there are 3 different dibrombenzenes, 
C 6 H 4 Br 2 ; 3 dinitrobenzenes, C 6 H 4 (N0 2 ) 2 , etc. For the difference 
in properties of the 3 isomers there is but one explanation, and 
that is based upon the fact that any hydrogen atom in the graphic 
benzene formula is placed symmetrically in relation to 2 pairs of 
hydrogen atoms, so that only three different substitution group- 
ings are possible. If the carbon atoms of the hexagon are num- 
bered as the hours on a dial, as shown below, omitting C and H, 




then with monovalent bromin it is possible to have only the three 
different positions for 2 substituted atoms, as shown below: 






Br 

1 : 2 Adjacent : 1:3 Unsymmetric : 1:4 Symmetric : 

ortho-position. meta-position. para-position. 

Where the 2 replacing atoms or groups occupy adjacent or 
consecutive positions, they form or^tf-compounds (orthos = straight), 
abbreviated as 0- or 1 : 2. When the arrangement is unsymmetric, 
it is called a meto-compound (meta = after), abbreviated m- or 
1:3. If symmetric in position, the product is a ^ra-compound 
(para = beside), abbreviated p- or 1 : 4. 

When 3 or 4 atoms of hydrogen are displaced by as many 
identical atoms or groups, 3 isomers result, and can be accounted 
for if their constitutions are as represented in the following for- 
29 



45° 



CYCLIC COMPOUNDS 



mulas for the 3 tetrabrombenzenes, using the simple unnumbered 
hexagon: 

Br Br Br 




Br 
1:2:3:4 Adjacent : 

ortho. 




1:8:3:5 Unsymmetric : 
meta. 




1:2:4:5 Symmetric : 



When the simple hexagon without letters is used instead of 
the formula C 6 H 6 , the conversion into a molecular formula is 
made by writing C 6 for the hexagon, allowing 1 hydrogen atom 
for each unoccupied corner, and writing the substituting atoms or 
radicals last. Thus: 

The three molecular formulas for the tetrabrombenzene, the 
graphic formulas of which have just been given, would be written 
C 6 H 2 Br 4 . To distinguish each of the three it is customary to 
precede the formula, or to append in parenthesis below the line 
the numbers indicating the angles taken by the replacing element: 

Ortho-C 6 H 2 Br 4(1)2)3)4) ; meta-C 6 H 2 Br 4(1;M)5) ; 
para-C 6 H 2 Br 4(1)2 , 4, 5). Or they may be written 
ortho-i : 2 : 3 : 4— C 6 H 2 Br 4 ; meta-i 12:3 5-C G H 2 Br 4 ; 
para- 1 : 2 14:5 — C 6 H 2 Br 4 . 

Another illustration is seen in the three different substances 
in which hydroxyl groups have been substituted for 2 hydrogen 
atoms. Careful research has established the fact that their con- 
stitutional formula should be written: 



OH 



OH 



OH 





Ortho- 



Meta- 




The one molecular formula for all three is C 6 H 6 2 , but this 
does not indicate their true structure, as dihydroxybenzenes . A 
complete conversion of the graphic hexagons is made as follows> 
the common name being given after each formula: 

0-dihydroxybeiizene = C 6 H 4 (OH) 2 , (1 _ 2) or pyrocatechin. 
#z-dihydroxybenzene = C 6 H 4 (OH) 2a _3), or resorcin. 
/-dihydroxybenzene = C 6 H 4 (OH) 2( w), or hydroquinon. 



BENZENE HYDROCARBONS 45 1 

General Properties of Aromatic Compounds.— The members 
of the benzene series, like those of the methane division, form 
halogen derivatives, and also alcohols, aldehyds, ketones, acids, 
nitro- and amido-compounds. Reference has already been made 
to their characteristic behavior and ready reaction with nitric acid. 
When the aromatic nitro-compounds are reduced, amido-com- 
pounds are produced, containing the amido-group, — NH 2 . Thus: 

C 6 H 5 .N0 2 + 6H = C 6 H 5 .NH 2 + 2 H 2 0. 

Nitrobenzene. Amidobenzene or anilin. 

When the amido-compounds are treated with nitrous acid in 
the cold, the products are diazo-compounds and not alcohols, as 
would be the case if fatty amins were so treated. The diazo- 
compounds are unstable bodies in which the hydrocarbon radi- 
cal is joined to a double atom of nitrogen, having one free affinity. 
Thus: diazobenzene is C 6 H 5 . N 2 . OH. 

Among the indirect derivatives of benzene are substances like 
diphenyl, C 6 H 5 — C 6 H 5 , which is regarded as formed by the union 
of two phenyl groups, resembling in this respect ethane or dimethyl, 
CH 3 — CH 3 . To explain the structure of some other hydrocarbons 
it must be assumed that combination occurs between 2 or more 
closed chains or nuclei which have 2 or more carbon atoms in com- 
mon. These substances are considered (p. 471) as polynucleated 
compounds, i. e. y containing more than one benzene nucleus. 





Naphthalene. Anthracene. 

Toluene (C 6 H 5 . CH 3 ) {toluol, methyl benzene) is so named 
because it can be obtained by dry distillation of balsam of Tolu 
and other resins, though it is always manufactured from coal-tar. 

It is a mobile liquid, pleasant smelling and inflammable, does 
not mix with water, resembling benzene, but having some prop- 
erties that are different, due to the methyl group in its composition. 
When oxidized the CH 3 of the methyl is changed to the acid 
group— COOH and water, but the benzene ring is unaltered. 

C 6 H 5 .CH 3 + 30 = C 6 H 5 .COOH + H 2 0. 

Methyl benzene. Benzoic acid. 

Xylene (C 6 H 4 (CH 3 ) 2 ) (xylol, dimethylbenzene) exists in the 
three isomeric forms, given below: 



452 CYCLIC COMPOUNDS 

CH, 






Orthoxylene. Metaxylene. Paraxyli 



These three varieties exist in coal-tar and in commercial xylol, 
and can be prepared synthetically from toluene. They are much 
alike in physical properties, being liquids, ethereal, of pleasant 
odor, and inflammable. In chemical properties there are certain 
marked differences. 

Cumene (C 6 H 3 (CH 3 ) 3 ) (trimethylbenzene) is usually obtained 
from coal-tar. It is the third of the homologues of benzene. 

Cymene (C 10 H 14 or C 6 H 4 . CH 3 . C 3 H 7 ) {parametkyl-propylbenzene) 
is an important pleasant-smelling hydrocarbon occurring in the 
ethereal essences of thyme and many other plants. It is easily 
prepared from camphor with phosphorus pentoxid: 

CioH 16 = C 10 H 14 + H 2 0. 

Camphor. Cymene. 

Its relation to turpentine is shown by the ease with which it 
is produced when that substance is oxidized by being heated with 
iodin: 

CioH 16 + O = C 10 H 14 + H 2 0. 

Turpentine. Cymene. 

Terpenes. — The hydrocarbon terebenthene, C 10 H 16 , consti- 
tuting pure oil of turpentine, terebinthina, U. S. P., is classed with 
its numerous isomers as terpenes. They may be regarded as 
derived from cymene by the addition of 2 atoms of hydrogen. 
They resemble turpentine chemically and physically, and are the 
essential constituents of many volatile oils, such as lemon, juniper, 
bergamot, rosemary, and other essences. They are polymerized 
when mixed with strong sulphuric acid; are converted to cymene 
by the halogens; and oxidized to several acids by nitric acid. 

Turpentine not being water soluble is given internally sus- 
pended in emulsum olei terebinthince, U. S. P., which contains gum 
acacia, syrup, oil of almond, and water. Dose: 1 fl. dr. (4 c.c). 
When oil of turpentine is treated with nitric acid and alcohol it is 
converted to terpin or turpentine camphor, a diatomic alcohol, 
Q H 18 (OH) 2 . When united with water this forms terpini hydras, 
U. S. P., in the form of colorless crystals of bitterish taste, perma- 
nent and water soluble. Dose, as an expectorant: 3 to 10 gr. 
(0.2-0.6 gm.). 



BENZENE HYDROXIDS 453 

Terebene, U. S. P., is obtained by the action of sulphuric acid on 
oil of turpentine. It consists chiefly of pinene, C 10 H 16 . It is a yel- 
lowish liquid of thyme-like odor and aromatic taste, forming 
resin by exposure to light. It is sparingly soluble in water, freely 
so in alcohol and ether, and is used internally as an expectorant, 
externally as an antiseptic. Dose: 5 to 10 Ttt (0.3-0.6 gm.). 

Stearoptens (camphors) are solid residues formed when tur- 
pentine and allied substances are distilled with steam. Camphor, 
U. S. P., a dextrogyrate ketone, C 9 H 16 CO, is a crystalline solid of 
characteristic odor, obtained from the camphor tree. Artificial 
camphor, C 10 H 16 HC1, is produced by the direct union of oil of 
turpentine and hydrochloric acid. Menthol, C 10 H 20 O, is a solid 
stearopten found in oil of peppermint. Thymol, U. S. P., C 10 H u O, 
is a solid cymylic phenol found in oil of thyme. It is crystalline, 
has a hot taste and aromatic odor. Very soluble in alcohol and 
ether, it is only sparingly so in w T ater. It is used in various sur- 
gical preparations as an efficient and agreeable' antiseptic. Thy- 
molis iodidum, U. S. P., C^H^C^L,, dithymol diodid, aristol, is a 
red, amorphous powder made by action of solution of iodin in 
potassium iodid on alcoholic solution of thymol. It contains 45 
per cent, iodin and is used as an aromatic substitute for iodoform 
in surgical dressings. It should be kept in amber-colored bottles. 
Eucalyptol, U. S. P., C 10 H 18 O, is a camphoraceous liquid found in 
oil of eucalyptus. It is insoluble in water, but soluble in alcohol 
and oils; used externally as an antiseptic, internally for lung 
diseases. 

BENZENE HYDROXIDS (Phenols) 

There are no fatty prototypes to the phenols. They contain 
the hydroxyl group substituted necessarily for an atom of hydro- 
gen of the benzene nucleus itself. Thus, ordinary phenol is 
C 6 H 5 . OH. Their constitution is different from that of a primary 
alcohol and hence when oxidized they do not yield an aldehyd, 
and, further on, an acid, nor form an ester with an acid, as does 
ethyl alcohol. 

In the higher homologues of benzene, which contain hydrogen 
in a side chain, there are substances which contain the hydroxyl 
group and behave on oxidation like ethyl alcohol. These are 
called aromatic alcohols and are illustrated in benzyl alcohol, 
C 6 H 5 . CH 2 OH, derived from toluene, C 6 H 5 . CH 3 , by the substitu- 
tion of — OH for an H of — CH 3 . These, when oxidized, form 
aromatic aldehyds, such as benzaldehyd, C 6 H 5 . COH; and aro- 
matic acids, such as benzoic acid, C 6 H 5 . CO OH. 

The two kinds of aromatic hydroxy-compounds then are 
(a) phenols and (b) aromatic alcohols. As all 6 of the hydrogen 
atoms of the benzene nucleus may be replaced by hydroxyl, the 




454 CYCLIC COMPOUNDS 

phenols may be monohydric, dihydric, trihydric, etc., according 
to the number of hydroxyl groups they contain. 

Carbolic acid, C 6 H 5 .OH, is a monohydric phenol, as is also 
cresol or hydroxytoluene, C 6 H 4 (CH 3 ) . OH. Resorcinol or dihy- 
droxybenzin is a dihydric phenol, and phloroglucinol, C 6 H 3 (OH) 3 , 
a trihydric phenol. 

Carbolic acid (C 6 H 5 . OH) (phenol, U. S. P., hydroxybenzene) 
occurs in traces in the urine, in the form of sulphophenolate of 
potassium, KC 6 H 5 S0 4 . This compound is derived from the 
OH proteid of the body. The sole source of the commer- 
cial article is coal-tar. The heavy oil is treated with 
sodium hydroxid, which combines with the phenol and 
then, on the addition of sulphuric acid, precipitates in 
a crude state as an oil. By more complex methods 
Phenol. j t can De obtained from brombenzene, nitrobenzene, 
anilin, or salicylic acid. 

It can be prepared from benzene indirectly by the following 
stages: Nitric acid (HON0 2 ) making nitrobenzene, which is 
reduced to amidobenzene by hydrogen: this by the action of 
nitrous acid (HONO) evolves free nitrogen, retaining hydroxyl. 

C 6 H 6 -> C 6 H 5 N0 2 -> C 6 H 5 .NH 2 -*- C 6 H 5 . OH 

Benzene. Nitrobenzene. Amidobenzene. Phenol. 

Acidum Carbolicum Impurum. — To purify carbolic acid 
further treatment is necessary with lime and hydrochloric acid, 
accompanied with successive distillations. Crude phenol is brown 
red, more acid than the pure, and has a stronger odor, due to 
cresols. 

Properties. — The volatilized product condenses in long color- 
less or faint red needles, having a characteristic odor, and when 
dissolved in much water a caustic, sweetish taste. It turns pink 
on exposure to light and deliquesces in moist air, but dissolves 
with difficulty in 15 parts of cold water, is readily soluble in boiling 
water, alcohol, ether, glycerin, chloroform, and the oils, but not 
in petroleum and benzin. The crystals melt at 43 ° C. (109. 4 F.), 
and, agitated with 10 per cent, of water or glycerin, they become 
phenol liquefactum, containing 86.4 per cent, by weight of absolute 
phenol. This is the most convenient form for dispensing or 
for other uses. It is a protoplasmic poison, coagulating albumin, 
and hence fatal to all forms of life. This makes it a potent bac- 
tericide, used especially in surgery for destroying the germs that 
infect wounds. Its reaction is neutral or feebly acid; it leaves a 
greasy, reddish stain upon blue litmus paper. With strong bases 
it forms carbolates or phenolates, in accordance with this equation: 

C 6 H 5 OH + NaHO = C 6 H 5 ONa + H 2 0. 



BENZENE HYDROXIDS 455 

With alkaline sulphates it forms non-poisonous salts of phenol- 
sulphonic acid, called sulphophenolates: 

+ NaHO. 



C 6 H 5 OH 


+ 


Na 2 S0 4 = 


= NaC 6 H 5 S0 4 


Phenol. 




Sodium 
sulphate. 


Sodium 
sulphophenolate. 



Dose: J to 2 gr. (0.03-0.13 gm.), well diluted. Among the 
official preparations are glycerite (1 part to 4 of glycerin); oint- 
ment, 3 per cent. 

When the crystals are triturated with the following substances 
a liquid or soft solid product is obtained: camphor, chloral 
hydrate, acetanilid, lead acetate, menthol, phenacetin, resorcin, 
salol. It coagulates collodion. 

Toxicology. — Owing to its common use as a disinfectant it can 
easily be bought by the suicide at any druggist's. Standing about 
the sick-room as an amber-colored oily liquid, it has been often 
mistaken for castor oil or alcoholic drinks. The death-rate from 
it places it in the list of suicidal poisons next to opium and its 
preparations and alkaloids. 

Symptoms. — These may be considered under two heads: Those 
due to the local effects, and those that are systemic in character. 
Upon the mouth, esophagus, stomach, and intestines it acts as an 
energetic corrosive poison. When absorbed it quickly arrests 
normal action in the nervous system, and causes death by paral- 
ysis of the respiratory and cardiac centers. 

If some of it touch the skin about the mouth, it causes burning, 
tingling, and numbness, followed by a white eschar. The cor- 
roded skin tissue separates in a few days and the white spot is 
succeeded by a brown stain. When it is swallowed the patient 
complains of a burning pain in the mouth, throat, and stomach, 
with or without retching and vomiting. There is distention of 
the abdomen and a strong odor of carbolic acid on the breath. 
The remote systemic effects are the same whether the point of 
absorption be the skin, the lungs, an open wound, the stomach, 
or other body cavities. The symptoms are muscular twitchings, 
weakness, pallor, nausea, clammy skin, headache, giddiness, de- 
lirium, thready and rapid pulse, irregular breathing. Lividity, 
coma, rarely convulsions, imperceptible pulse, and halting respi- 
ration usher in the final scene. In the meantime the urine is 
albuminous and bloody. 

The greater part of the phenol changes by contact with the 
sulphates in the body to sulphophenolates and the simple sul- 
phates disappear from the urine. The normal ratio of the simple 
sulphates of the urine to the conjugate sulphates is as 10 : 1. A 
portion of the phenol is changed to phenol-glycuronic acid and is 



456 CYCLIC COMPOUNDS 

eliminated as harmless conjugate alkali salts. A considerable 
portion is oxidized to the dihydroxybenzenes, pyrocatechol, and 
hydroquinol. These also form conjugate sulphates. In the 
urine they oxidize further to quinon (C 6 H 4 2 ), a dark greenish 
or black substance. 

Fatal Dose. — Though 15 gr. (1 gm.) would cause dangerous 
symptoms when taken by the stomach, a fatal result is not likely 
unless 60 gr. (4 gm.) have been taken. Recovery has ensued 
after 1 fl. oz. (30 c.c.) has been swallowed. Absorbed from a 
wound, from the rectum or uterus, 15 gr. (1 gm.) would probably 
kill. 

Fatal Period. — Large doses or external application to open cuts 
may destroy life in ten minutes. Usually death is not delayed 
beyond two hours, though there are cases where death has not 
occurred for several days. 

Treatment. — The local anesthesia prevents the action of ordi- 
nary emetics. A liberal dose of whisky or alcohol is often given 
as a diluent. It should be followed by the introduction of the soft 
stomach-tube and washing out with solution of sodium sulphate 
until the contents of the stomach lose their peculiar odor. Sodium 
sulphate forms the relatively harmless sodium phenol-sulphonate. 
Dependence should not be placed on alcohol as an antidote. 

If carbolic acid be applied to the skin, the mucous membrane, 
or open wound, and quickly followed by a lotion of alcohol, the 
corrosive action does not occur, and there are no constitutional 
symptoms. Some of this controlling action may be the effect of 
prompt dilution with a perfect solvent. It is not unlikely that 
alcohol, as a solvent, causes the molecule to dissociate in different 
ions from those that form in aqueous solution. If ferric chlorid 
be added to the solution in water, a violet-colored reaction ap- 
pears; with the alcoholic solution it is brownish. If, however, 
water be added to the mixture with alcohol, the brownish liquid 
changes to violet. If the alcohol and carbolic acid be allowed 
to remain in the stomach, osmotic flow of water dilutes the alcohol, 
and in a few minutes absorption begins and the effects are those 
of a poisonous aqueous solution. To obviate this danger the 
lavage must remove the poison as soon as alcohol has been given. 
The antidotes of approved value are sodium sulphate, raw eggs, 
milk, and saccharate of lime. 

For the coma and cardiac depression benefit may follow alter- 
nations of hot and cold affusions and the administration of hypo- 
dermic injections of atropin or strychnin. For failure of breathing 
resort should be had to artificial respiration. 

Postmortem Appearances. — The corroded spots about the lips, 
and the mucous lining of the mouth and esophagus are white and 



BENZENE HYDROXIDS 457 

corrugated. The stomach mucous membrane is hardened, 
white in patches, wrinkled, denuded in parts, showing the red 
inflamed structure beneath. Hemorrhagic points show where 
blood has been poured into the gastric contents. 

Like changes appear in the duodenum. The characteristic 
odor of carbolic acid is discernible in the body, in the fluid of 
the ventricles of the brain, and in the urine. The urine is dark- 
greenish and shows little reaction to barium chlorid, the sulphates 
being conjugate with phenol. 

Tests. — 1. The odor is characteristic. 

2. Carbolic acid coagulates albumin and also the clear collo- 
dion solution. 

3. A trace of ferric chlorid gives an amethystine-blue color to 
aqueous solutions of carbolic acid. This test is interfered with 
by alcohol, ammonia, the mineral acids, and excess of ferric chlorid, 
all of which prevent the full development of the reaction. Cre- 
osote turns ferric chlorid brown and green. 

4. Strong bromin water added to weak carbolated solutions 
precipitates white crystals of trior omphenol. 

5. When boiled with MillorCs reagent, 1 made fresh, solutions 
of carbolic acid turn red. If the change does not occur, it may 
require the addition of a few drops of nitric acid. The same 
reaction is produced by other phenols and the proteids, as is shown 
when pieces of dry albumin or dry bread are boiled in Millon's 
reagent; they turn dark red. 

This reaction always denotes the OH group attached to the 
benzene ring (oxyphenyl). Given by the proteids it indicates in 
them the presence of this same combination existing in the cyclic 
compound tyrosin (p. 500). 

6. A solution of carbolic acid is gently warmed with a small 
quantity of ammonia water and a few drops of solution of chlo- 
rinated lime. A blue color is. produced, which changes to red on 
being acidulated. If the blue color fade, it may be restored by 
the addition of more of the chlorinated lime. 

Detection. — A portion of the blood or the liver is digested for 
one hour with dilute sulphuric acid (2 per cent.). After straining, 
the liquid is mixed with dilute alcohol (1 to 3) and filtered. Having 
treated 30 c.c. of this with a few drops of ammonia, it is added to 
a reagent prepared as follows: To 20 c.c. of a solution of ani- 
lin containing 3 drops to 100 c.c. of water, add sodium hypo- 
chlorite sufficient to make a brown color. When the extract from 

1 A mixture of mercuric and mercurous nitrates containing some free nitrous acid, 
made by adding 5 c.c. of fuming nitric acid to 0.5 c.c. of mercury. The mercury 
must dissolve without boiling and the solution is then diluted with two volumes 
of water, and after several hours decanted. It does not keep long. 



45& CYCLIC COMPOUNDS 

the liver or blood is added to this reagent a permanent blue color 
indicates the presence of carbolic acid. 

The urine is titrated with BaCl 2 to see if the simple sulphates 
are less than normal. It is then filtered from BaS0 4 and boiled 
with HC1 to break up the sulphophenolates. Tested again with 
BaCl 2 , if a heavier precipitate falls, there is excess of sulpho- 
phenolates, due to phenol (p. 589). 

Phenolsulphonic acid (C 6 H 4 (OH) . S0 3 H) (sulphocarbolk acid) 
is formed when phenol is dissolved in concentrated sulphuric acid 
(for Sulphonic Acids see p. 415): 

C 6 H 5 OH + H 2 S0 4 = C 6 H 4 (OH) . SO3H + H 2 0. 

It is a syrupy liquid having a red color and feeble odor, and 
is freely soluble in water. It behaves as a monobasic acid, forming 
sulphocarbolates of sodium, potassium, and other metals. The 
acid and its salts prevent fermentation, destroying low forms 
of animal and vegetable life, and are valued in medicine as anti- 
septics, being less irritating and poisonous than carbolic acid. 
The commercial aseptol or sozolic acid is a 30-per cent, solution 
of 0-phenolsulphonic acid in water, used diluted to 10 per cent, as 
an antiseptic. 

After the ingestion of phenol it is eliminated by the urine as a 
potassium sulphophenolate (KC 6 H 5 S0 4 ), a conjugate or ethereal 
sulphate. 

Sodii phenolsulphonas, U. S. P., C 6 H 4 (OH)SO s Na, is a white 
crystalline salt, used locally as an antiseptic, and internally in 
fermentative dyspepsia. Dose: 10 to 30 gr. (0.6-2 gm.). 

Zinci phenolsulphonas, U. S. P., Zn(C 6 H 5 4 S) 2 + 8H 2 occurs 
in colorless, tabular crystals used to make astringent solutions. 

Ichthyol is the ammonium salt of a complex ichthyosulphonic 
acid having the formula C 2S H 36 S 3 6 (NH 4 ) 2 . It is prepared 
from a mineral pitch found in the Tyrol, containing fossil fishes. 
It is a dark brown thick liquid with an unpleasant smell, soluble 
in water, oils, and glycerin. Applied locally, it is analgesic and 
antiphlogistic. It is incompatible with acids, alkalis, and alkaloids. 

Trinitrophenol (C 6 H 2 (N0 2 ) 3 . OH) (Picric Acid).— When phe- 
nol is treated with dilute nitric acid it is converted into ortho- 
and ^ara-nitrophenol, which separate as a dark brown oil or 
resinous mass. If this or a solution of phenol itself be gently 
heated with a few drops of nitric acid, 3 groups of N0 2 are taken 
up, the liquid turns yellow, and on cooling crystals of picric acid 
separate. 

The constitution of trinitrophenol is represented by the for- 
mula: 



BENZENE 


HYDROXIDS 




OH 




no/ 


) 

N0 2 


*o 2 



459 



It is the yellow substance formed by the action of concentrated 
nitric acid on woolen and silk fabrics, albumin, bread, and other 
nitrogenous animal matter, indigo, resins, leather, etc. 

This xanthoproteic reaction always indicates the presence of 
the benzene ring, but not necessarily with the OH group attached, 
as in phenol. In the proteids are found not only tyrosin, but 
■phenylalanine both of which give this yellow color with nitric acid, 
due to trinitrophenol (picric acid). It is crystalline, odorless, 
intensely bitter, markedly acid, and slightly soluble in cold, but 
more easily so in hot water. It has the properties of a monobasic 
acid, readily decomposing carbonates and forming salts. Potas- 
sium picrate, C 6 H 2 (N0 2 ) 3 . OK, like the sodium and ammonium 
compounds, is a yellow crystalline substance, explosive under 
the action of heat or percussion. Picric acid itself burns quietly 
when ignited with caution, but under percussion or sudden heat 
explodes violently. It is used as a yellow dye for silk and wool. 
It is a valuable precipitant for albumin in Esbach's test, and for 
the alkaloids. Heated with glucose in alkaline solutions it pro- 
duces a deep red color. Sometimes it is used as an adulterant 
for beer, because of its bitter taste and yellow color. 

Toxicology. — Picric acid is sometimes applied to the skin in 
the treatment of skin diseases and burns. Absorbed from the 
skin or taken internally it may cause poisonous symptoms. 
Locally it irritates the skin, causing eczema; taken by the mouth 
the mucous membrane is irritated, by virtue of the necrosis due to 
the precipitation of the albumin in the tissues. There are vomiting 
of yellow matter, abdominal pain, and diarrhea with yellow stools. 
Without bile, the urine becomes red-brown owing to the presence 
of picraminic acid. The blood corpuscles decompose and form 
methemoglobin. The eyes turn yellow and the skin itches, as in 
jaundice. Great weakness, stupor, and convulsions precede 
collapse. 

Fatal Dose. — Poisoning has followed 30 gr. (2 gm.), but recov- 
ery has occurred after 90 gr. (6 gm.). 

Treatment. — The stomach should be thoroughly washed out, 
and the bowels evacuated by enemata. The antidotes are proteins, 
as in raw eggs and milk. Glucose reduces the picric acid to a less 
injurious substance, and may be given freely. 

Tests. — Having acidulated the material with sulphuric acid, 



460 CYCLIC COMPOUNDS 

ether is shaken with it to extract the picric acid. The residue 
after evaporation is dissolved in water, and a thread of .cotton and 
one of wool placed in it. It is then acidified and warmed. The 
cotton is not dyed, but the wool stains yellow, yielding the color 
when immersed in alkaline solutions. When an alkaline solution 
of it is warmed with potassium cyanid a blood-red color is produced. 

Cresol (C 6 H 4 (CH 3 ) . OH) (Cresylic Acids, Hydroxy toluenes). — 
The three next homologues of phenol are the ortho-, meta-, and 
para-cresols, occurring in coal-tar and separable from it by frac- 
tional distillation. They resemble carbolic acid in their feeble 
solubility in water, in forming compounds with potassium and 
sodium, and in giving the bluish color with ferric chlorid. 

Liquor cresolis compositus, U. S. P., is a solution of cresol in 
a soapy liquid made with linseed oil and potassium hydroxid. 
It is miscible with water in all proportions, and is a reliable antl 
convenient disinfectant for the hands and instruments in the 
proportion of one part to twenty of warm water. 

Creolin is a black syrupy antiseptic, containing a number of 
aromatic substances, chiefly cresols. It is less poisonous than 
carbolic acid. Dose: 5 to 15 min. (0.3-1 gm.). 

Lysol is an oily liquid, saponified by boiling tar, oils, fat, and 
resin with alkali. It is an impure paracresol containing soap, 
soluble in water; antiseptic and less poisonous than carbolic acid. 

Creosote is a complex mixture of phenol, cresol, guaiacol, 
C 7 H 8 2 , creosol, C 8 H 10 O 2 , phlorol, C 8 H 10 O, and other aromatic 
compounds produced by distillation of wood-tar. It is an oily 
liquid of peculiar odor and burning taste; colorless when fresh, 
but turning brownish on exposure to light. It is often adulterated 
with carbolic acid, which it resembles in being an antiseptic and 
a powerful irritant poison. It is used as a local application for 
toothache and a caustic for warts. It is to be distinguished from 
carbolic acid in its feebler solubility, in not crystallizing on cool- 
ing, in not coagulating the official collodium, and in giving with 
ferric chlorid a transient brownish, and not a bluish coloration. 

Toxicology. — The poisonous effects are much like those of 
carbolic acid and guaiacol. 

Dihydric Phenols (C 6 H 4 (OH) 2 ).— The three isomeric dihy- 
droxybenzenes are well known and have much importance under 
the names pyrocatechol, resorcinol, and hydroquinol. Their 
respective formulas are given in another place (p. 450). 

Pyrocatechin, Catechol, 0-C 6 H 4 (OH) 2 , is eliminated in traces 
by the human urine, having entered the circulation as a product of 
intestinal putrefaction. It also occurs in the drug catechu. It 
can be prepared by fusing phenolsulphonic acid with potash. 

It is a colorless crystalline substance, soluble in water. In 



BENZENE HYDROXXDS 46 1 

weak solution it can reduce Fehling's solution, and hence create 
a fallacy in testing for glucose in the urine. To detect it in the 
urine a considerable quantity of that fluid must be boiled with 
hydrochloric acid and then extracted with ether. The residue 
after evaporation is dissolved in water, and this solution gives 
with ferric chlorid a dark-green coloration which, on the addition 
of sodium bicarbonate, changes to violet and later to red. 

This green color with ferric chlorid is given with all the dihy- 
droxybenzenes. The preparation extracted from the supra- 
renal gland, called adrenalin, yields the same reaction, showing 
the presence of catechol as a component of the active principle. 
Its constitution is believed to be represented by the formula: 

OH 

OH 




CHOH . CIL, . NHCH 3 



Guaiacol, U. S. P., C 6 H 4 . OH . OCH 3 , methyl-pyrocatechin, is 
a crystalline solid contained in the tar of beechwood, from which 
it is obtained by the fractional distillation of creosote. In absolute 
guaiacol it occurs as an oily liquid of aromatic odor, slightly sol- 
uble in water, freely so in alcohol and ether. It is used in med- 
icine. Dose: 3 to 15 gr. (0.2-1 gm.). Its pharmaceutic com- 
pounds are the carbonate, benzoate, iodid, and salicylate. 

Resorcin (C 6 H 4 (OH) 2 ) (resorcinol, m-dihydroxybenzene) is pre- 
pared by the action of fused potash on benzene-w-disulphonic 
acid. It can also be obtained by dry distillation of extract of 
Brazil wood, and by melting with caustic potash various resins, 
such as galbanum. Its structure has been referred to previously 

(P- 45°)- 

It is a crystalline, colorless (turning red on exposure), sweetish 
substance, freely soluble in water, alcohol, and ether. It is odor- 
less and antiseptic. Its aqueous solution turns a violet color with 
ferric chlorid. Under the name Boas' reagent (p. 549) an alco- 
holic solution of resorcin and cane-sugar is used as a delicate 
test for free hydrochloric acid. 

When the resorcin is heated with phthalic anhydrid in a dry tube, 
a reddish mass is formed which, when dissolved in soda, gives a 
brownish solution. Added to water, this gives a beautiful red 
color with a yellow-green fluorescence. This shows the presence 
of fluorescein (resorcin-phthalein), C 20 H 12 O 5 , an important dye- 
stuff, from which is manufactured its sodium salt, uranin, 
C 20 II 10 O 5 Na 2 , another valuable dye. When fluorescein is treated 



462 CYCLIC COMPOUNDS 

with bromin, 4 atoms of hydrogen in the resorcin nuclei are dis- 
placed by bromin, forming eosin, a deep red dye with green fluor- 
escence. Its potassium salt is a brownish powder which stains 
tissues a beautiful pink. 

The medical effects of resorcin are those of phenol. It is used 
externally in skin diseases and in surgical dressings. By absorp- 
tion from the skin it may cause the toxic nervous symptoms of 
phenol. 

Dose of resorcin for seasickness: 2 gr. (0.13 gm.) every two 
hours; for antipyretic effects: 15 to 30 gr. (1-2 gm.). Its incorn- 
patibles are albumin, alkalis, antipyrin, acetanilid, exalgin, cam- 
phor, menthol, urethan, ferric chlorid, and spts. aetheris nitrosi. 

Hydroquinol (C 6 H 4 (OH) 2 ) (quinol, p-dihydroxybenzene) is a 
crystalline substance, readily soluble in water, and used in photog- 
raphy. It is an antipyretic in doses of 15 gr. (1 gm.). 

Pyrocatechol, resorcinol, and hydroquinol are reducing agents,, 
taking oxygen from other compounds and in the presence of alkalis 
even, from the air, turning to dark-green quinone (C 6 H 4 2 ). 
Hydroquinol is the most active in this respect. 

Trihydric Phenols (C 6 H 3 (OH) 3 ).— The three trihydric iso- 
mers possible in theory are all known; their constitutions are 
represented by the three formulas: 



OH 


OH 


OH 


/y 


A 


A». 


k> 


Hoi JoH 


V . 


Pyrogallol. 
1:2: 3 — Trihydroxybenzene. 


Phloroglucinol. 
1:3: 5 — Trihydroxybenzene. 


Hydroxyhydroquinol. 
1:2: 4 — Trihydroxybenzene. 



Pyrogallol (pyrogallic acid) is prepared by heating gallic acid„ 
at about 200 C. (392 ° F.), until C0 2 ceases to be evolved: 

C 6 H 2 (OH) 3 .COOH = C 6 H 3 (OH) 3 + C0 2 . 

Gallic acid. Pyrogallol. 

It is a colorless crystalline substance readily soluble in water,, 
and giving with ferric chlorid a red color. When ferrous sul- 
phate is mixed with the ferric chlorid it yields a dark-blue color. 
Dissolved in alkalis, the solution turns black in the air from 
absorption of oxygen. By shaking this alkaline solution in a. 
mixture of gases of known volume, the amount of shrinkage 
determines the oxygen present. In the presence of light and the 
salts of gold, silver, and mercury, it is oxidized to oxalic and acetic 



AROMATIC ALCOHOLS 463 

acids, while reducing the salts to the metallic state. Like hydro- 
quinol, it is used as a developer in photography. It has been 
taken by mistake, with fatal results. Absorbed, it poisons the red 
corpuscles, causing them to shrink and lose their hemoglobin, 
which changes to methemoglobin, a brownish substance. This 
leads to jaundice and nephritis. 

The symptoms are headache, chills, vomiting, cyanosis, dark 
urine, collapse, tremor, coma. The poison must be washed from 
the skin and the stomach. Stimulants and hypodermic injections 
of salt solution are called for. 

Detection. — The material is shaken with ether to extract the 
pyrogallol. This is then tested with ferric chlorid and the silver 
salts to show its reducing action. Millon's reagent gives a red 
color with it. 

Phloroglucin, i : 3 : 5 — C 6 H 3 (OH) 3 , is obtained by fusing 
phenol with potash. It is colorless, crystalline, very soluble in 
water, and sweetish in taste. In making Gunzburg's reagent (p. 
549) it is dissolved in alcohol with vanillin to detect free hydro- 
chloric acid. A test for pentoses is made by warming with a mix- 
ture of phloroglucinol and hydrochloric acid; a deep red color 
develops. 



OXYGEN DERIVATIVES OF BENZENE 

AROMATIC ALCOHOLS 

When hydroxyl groups are substituted for the hydrogen atoms 
of the side chain in the aromatic hydrocarbons higher than ben- 
zene, substances are produced behaving like alcohols. Like the 
corresponding fatty alcohols, they are produced when the halogen 
derivatives are heated with water or weak alkalis, or by reducing 
the aldehyds. Thus, the simplest members: 

C 6 H 5 . COH + 2H = C 6 H 5 . CH 2 . OH. 

Benzyl aldehyd. 

Benzyl Alcohol. — This compound contains the group: car- 
binol, — CH 2 . OH, and C 6 H 5 , or phenyl, and is 
therefore called phenyl carbinol. It occurs in 
the resins of styrax and balsams of Peru and ^CHj.OH 

Tolu. It is a colorless liquid, which oxidizes first 
into benzaldehyd and then into benzoic acid. 




464 CYCLIC COMPOUNDS 

AROMATIC ALDEHYDS 

These hold the same relationship to alcohols and acids as that 
existing between their analogues of the fatty series. They are the 
alcohols dehydrogenated. 

Benzaldehyd (C 7 H e O or C 6 H 5 COH) (Oil of Bitter Almond). 
— This is obtained when the glucosid, amygdalin, 

Oand the ferment, emulsin (occurring in bitter al- 
COH monds), are brought into the presence of water. 
As these are present in the kernels of cherries, 
peaches, and the bark and leaves of the cherry 
laurel, the same reaction results when these are 
macerated in water. The amygdalin is gradually decomposed 
into benzaldehyd, glucose, and hydrocyanic acid: 

C 20 H 27 NO n + 2 H 2 = 2C 6 H 12 6 + HCN + C 7 H e O 

Amygdalin. Glucose. Hydrocyanic acid. Benzaldehyd. 

By distillation, an oil (oleum amygdala amarce) comes over 
which contains by weight 85 per cent, of benzaldehyd and 2 to 
4 per cent, of hydrocyanic acid. In the laboratory benzaldehyd is 
prepared from benzal chlorid with dilute sulphuric acid. 

It is a colorless liquid with the smell of almond and a burning 
taste, sparingly soluble in water, but freely in alcohol. In the 
•crude oil of bitter almonds its association with hydrocyanic acid 
makes it poisonous (p. 194). 

Vanillin. — m-Methoxy-p-oxybenzaldehyd, C 6 H 3 .COH.(O.CH 3 ).- 
OH, is the odoriferous principle of vanilla occurring in colorless 
needles. The coniferous plants yield a glucosid, coniferin, which 
by oxidation gives vanillin. 

Salicylic Aldehyd. — Salicylate salicylous acid, 0-oxybenzalde- 
hyd, C 6 H 7 (OH)COH, is the odoriferous principle in the essential 
oil of Spircea ulmaria. It can be made by oxidizing salicin. It 
is an aromatic colorless oil having the properties of an aldehyd 
and a phenol. 

AROMATIC ACIDS 

The acids of the benzene series containing carboxyl, —CO OH, 
are derived by substituting 1 or more such groups for the same 
number of hydrogen atoms. Substitution in the nucleus benzene 
itself yields, beside the simplest member, benzoic acid, C 6 H 5 .- 
COOH, the 3 isomeric phthalic acids, dicarboxylic, C 6 H 4 (COOH) 2 ; 
the 3 tricarboxylic, C 6 H 3 (COOH) 3 , etc. Toluene and the higher 
members having methane side chains yield 2 classes of acids, 
according as the substitution is in the nucleus or in the side chain. 
Thus: there are 3 isomeric toluic acids, C 6 H 4 . CH 3 . COOH, of 
the first class, and phenyl acetic acid, C 6 H 5 . CH 2 . COOH, of the 
second class. 




AROMATIC ACIDS 465 

The only important aromatic carboxylic acid is benzoic. All 
aromatic hydrocarbons which contain only 1 side chain yield 
benzoic acid when oxidized with nitric or chromic acid. Thus: 

C 6 H 5 .CH 3 + 3O = C 6 H 5 .COOH + H 2 0. 

Toluene. Benzoic acid. 

When the hydrocarbons have 2 side chains, phthalic acid is 
formed. 

The aromatic acids crystallize, are slightly soluble in water, 
and when heated usually volatilize without decomposing. 

Benzoic acid, C 7 H 6 2 , receives its name from its original 
source, gum benzoin. It is also present in balsam of COOH 

Peru. As the compound hippuric acid or benzoyl- 
glycin it is present in the urine of herbivora. From 
the latter combination it can be obtained by boiling 
with hydrochloric acid: 

C 6 H 5 .CO.NH. CH 2 COOH + HC1 + H 2 = 

Hippuric acid. 

C 6 H 5 COOH + NH 2 . CH 2 . COOH, HC1 

Benzoic acid. Glycin hydrochlorid. 

It can be sublimed from gum benzoin, or be prepared by oxidizing 
benzaldehyd, benzyl alcohol, or toluene. 

Properties. — It forms white glistening plates which sublime at 
ioo° C. (212 F.), melt at 120 C. (248 F.), boil at 250 C. 
(482 ° F.). Its vapor, derived from benzoin, has an aromatic 
odor, but the synthetic acid is odorless. Sparingly soluble, in 
cold water, it dissolves readily in hot water, alcohol, and ether. 
As a monobasic acid it forms but 1 series of salts, such as the 
official benzoates of sodium, lithium, calcium, and ammonium. 

Test. — When benzoic acid or its salts are in neutralized solu- 
tion they yield to neutral ferric chlorid a red or flesh-colored 
precipitate of ferric benzoate. 

Medical Uses. — The U. S. Board of Food Inspection (1908) 
regard benzoic acid and sodium benzoate as harmful when used 
to preserve food. The practice is very extensive, and though at 
present permitted in quantities not to exceed one-tenth of 1 per 
cent., eventually it will be prohibited altogether. Benzoic acid is 
an antiseptic and antipyretic. Given in full doses, it increases the 
acidity of the urine by its conversion in the body into hippuric acid. 
It is used to correct the alkaline urine of cystitis. Dose: 5 to 20 gr. 
(0.3-1.25 gm.). 

Excretion of Cyclic Compounds. — Aromatic bodies are very 
stable, owing to the resistance offered to oxidation by the benzene 
3° 



466 CYCLIC COMPOUNDS 

nucleus. Once absorbed, the nucleus persists, though when 
eliminated it has formed a new combination. In another place 
(p. 455) it has been stated that phenol containing the OH ben- 
zene ring is absorbed by the intestines and passes out by the 
kidneys as an acid ester, either as potassium sulphophenolate or 
phenol glycuronate. So benzoic acid having a CO OH benzene 
ring, if it be fed to an animal, is excreted as an amin-ester of glyco- 
coll, viz., hippuric acid. 

C 6 H 5 COOH + CH 2 NH 2 COOH = 

Benzoic acid. Glycocoll. 

C 6 H 5 .CO.NHCH 2 COOH + H 2 0. 

Hippuric acid. 

The suffix -uric acid is used to denote a glycocoll amin-ester; 
thus, salicylic acid escapes from the body as salicyluric acid. 
This termination merely means that it is an acid in the urine, not 
that it is akin to uric acid. 

Benzoyl chlorid, C 6 H 5 COCl, is prepared by the action of 
hydrochloric acid on benzoic acid: 

C 6 H 5 COOH + HC1 = C 6 H 5 COCl + H 2 0. 

Its chlorin atom is readily replaced by an alcoholic group to form 
an ester or to an amino- (NH 2 ) group to form an amin-ester of 
benzoyl, C 6 H 5 . CO. Thus in an alkaline solution: 

C 2 H 5 C0C1 + HOC 2 H 5 = C 6 H 5 COOC 2 H 5 + HC1. 

Ethyl alcohol. Benzoyl ethyl ester. 

The alcohol has been benzoylized. When the monosaccharids are 
thus treated they make crystallizable products, proving the presence 
of an alcoholic or hydroxyl group in their constitution. 

Phthalic Acid (C 6 H 4 (COOH) 2 ).— The simplest and most im- 
portant dicarboxylic acids are the 3 whose structure is represented 
below. They may be prepared by oxidizing the corresponding 
dimethylbenzenes with nitric acid. 

COOH COOH COOH 

^COOH 








COOH 




Orthophthalic acid. Isophthalic acid. Terephthalic acid. 

When strongly heated orthophthalic acid is converted to phthalic 

CO 
anhydrid, C 6 H 4 <p O >0. When this last compound is heated 



HYDROXY- OR PHENOL ACIDS 467 

with phenol and zinc chlorid the product is phenolphthalein, 
C 20 H 14 O 4 , water being eliminated. This occurs in yellowish 
crystals, which when dissolved, 1 per cent., in alcohol make a 
valuable indicator in alkalimetry. Added to alkaline solutions it 
forms a salt which imparts a deep-pink color, destroyed, however, 
by the addition of acids (p. 126). It is a complex derivative 
of phthalic acid containing three benzene rings. It is given as a 
painless cathartic. Dose: 1-5 gr. (0.06-0.30 gm.). "Phthalins" 
are a different group of little importance. 

HYDROXY- OR PHENOL ACIDS 

These are derived from benzoic acid and its homologues as 
glycollic acid is from acetic acid — that is, by substitution of hy- 
droxyl for hydrogen. When that group is united to the carbon 
of the nucleus, the compound has something of the character 
of phenols. Thus, the 3 isomeric hydroxybenzoic acids, C 6 H 4 (OH). 
COOH, are not only carboxylic acids (having — COOH), but 
are also phenols (having —OH). This class includes the im- 
portant acids — salicylic, gallic, and tannic. 

They may be obtained indirectly from benzoic acid or its 
homologues by the same reactions given for the preparation of 
phenol from benzene — that is, first, a nitro-compound; second, 
reduction to an amido-compound; and, finally, treatment with 
nitrous acid. 

Another synthetic method is to prepare the aldehyd by the 
action of chloroform on the corresponding phenol in the presence 
of caustic soda. Exposure to the air oxidizes the aldehyd into the 
acid. 

The hydroxy acids are colorless, crystalline, and soluble in 
water. They form salts when treated with metallic carbonates 
or hydroxids; the hydrogen of the carboxyl, —COOH, is dis- 
placed, and, with excess of alkali, that of the hydroxyl also. 

Salicylic acid (C 6 H 4 (OH) . COOH) (o-hydroxybenzoic acid) 

occurs in considerable amount in oil of winter- 

OH 
green (gaultheria) as methyl salicylate. It may ,. 

also be obtained by oxidizing salicyl alcohol or / y^OOH 

salicyl aldehyd. 

Salicylic acid is prepared on a commercial \ S 

scale as follows: Carbolic acid is treated with 

caustic soda, forming sodium phenolate. This is saturated with 

carbon dioxid under pressure, and heated at 200 C. (392 F.) to 

form sodium phenyl carbonate: 

C 6 H 5 . ONa + C0 2 = C 6 H 5 . O. COONa 

Sodium phenolate. Sodium phenyl carbonate. 



468 CYCLIC COMPOUNDS 

By heating this product in the vapor of carbon dioxid under 
pressure there is a migration of atoms in the molecule, with com- 
plete transformation to sodium salicylate: 

C 6 H 5 .O.COONa = C 6 H 4 . OH . COONa 

Sodium phenyl carbonate. Sodium salicylate. 

Properties. — Salicylic acid is a white, crystalline solid, odorless, 
sweetish, and acrid in taste, sparingly soluble in cold, but readily 
in hot water, alcohol, or ether. It sublimes at 200 ° C. (392 ° F.). 
The monometallic salts, such as sodium salicylate, are soluble; 
the dibasic dimetallic salts, such as C 6 H 4 (ONa) . COONa, are 
decomposed by carbonic acid with the formation of the mono- 
metallic salt and a carbonate. With neutral ferric chlorid it gives 
an intense violet color. 

Salicylic acid is a valuable antiseptic and antirheumatic, pref- 
erable to carbolic acid as a disinfectant because it is odorless. 

It is often added to liquors and foods as a preservative. Dose: 
10 to 15 gr. (0.6-1 gm.) every two hours or less. 

Toxicology. — Salicylic acid figures as a poison from accidental 
overdosing and from its widespread use in preserving food and 
drink. In the body it becomes conjugate with glycocoll and is 
eliminated partly as salicyluric acid and partly unaltered. 

Symptoms. — These are pain and irritation of the pharynx and 
stomach, difficulty in swallowing, vomiting, diarrhea. The face 
is flushed and the head feels full, with roaring in the ears. Vision 
becomes dim and the mind confused, delirious, and, later, com- 
atose. The urine may be albuminous and discolored by hematin. 
The pulse is weak and breathing labored. When minute quan- 
tities are taken daily in food the appetite suffers, digestion is im- 
paired, diarrhea alternates with constipation, eczema appears, the 
mind is depressed, and the urine may be albuminous. 

Fatal Dose. — One ounce (31 gm.) has proved fatal after four 
days. A less quantity would probably be fatal were the heart or 
kidneys diseased. 

Treatment. — Evacuation and washing out of the stomach should 
be followed by the free use of raw eggs and milk. 

Tests. — Beside the tests given for phenol (p. 457) with bromin 
water, ferric chlorid, and Millon's reagent, a more characteristic 
one is used. The material is put in a test-tube with methyl alco- 
hol and one-half as much sulphuric acid. Warmed, cooled, and 
warmed again, the odor of oil of wintergreen is noted. 

To detect salicylic acid in beer, wine, milk, and food: acidify 
100 c.c. with dilute sulphuric acid and then extract with equal 
parts of benzine and ether. Evaporate the extract after separa- 




HYDROXY- OR PHENOL ACIDS 469 

tion, and test the residue with ferric chlorid; a violet color is pro- 
duced. 

Acetyl-salicylic acid, C 6 H 4 . COOH(C 2 H 3 0) {aspirin) occurs 
in white needles, soluble in 100 parts of water, but freely in alcohol 
and ether. It is used like sodium salicylate for rheumatism in 
doses of 5 to 20 gr. (0.32-20 gm.). Salicylic acid is set free in the 
intestines. It is decomposed by heat, moisture, or alkalies. 

Methyl salicylate (C 6 H 4 (OH) . COOCH 3 ) QH 

{artificial oil of wintergreen) is an ester prepared 
by distilling a mixture of salicylic acid in methyl f \,COO.CH s 
alcohol and sulphuric acid. It has the agree- 
able odor and chemical and antirheumatic prop- 
erties of the natural oil obtained from plants. 

Phenyl salicylate (C 6 H 4 (OH) . COOC 6 H 5 ) (salol) is an ester 
obtained by heating salicylic acid to 220 C. 
(428 ° F.); or by dehydrating a mixture of phenol /\ 
and salicylic acid. It is a white, faintly aro- / Ncoo.CH 
matic, crystalline powder. Almost insoluble I J 

in water, it dissolves readily in ether, chloroform, \.y/ 
alcohol, and fatty oils. Passing undecomposed 
through the stomach, the intestines break it up into phenol and 
salicylic acid. 

It is antirheumatic, antipyretic, and an intestinal antiseptic. 
Dose: 5 to 10 gr. (0.3-0.6 gm.). 

Overdoses cause a blending of the poisonous symptoms of sali- 
cylic acid and phenol. In the urine will be found both of these 
agents, detected by the tests given elsewhere. 

It is incompatible with ferric chlorid, chloral, camphor, bromin 
water, and carbolic acid. 

Salophen (C 6 H 4 OHCOO) . C 6 H 4 NH(C 2 H 3 0) {acetparamido- 
salol). — This is the salicylic ester of 1, 4-acetamidophenol derived 
from salol, but with acetyl and amino groups. 

It contains 51 per cent, of salicylic acid, is a white, tasteless, 
odorless powder, insoluble in water, but soluble in alcohol and ether. 
Its action is antirheumatic, antipyretic, and analgesic in doses of 
10 gr. (0.6 gm.). Passing the stomach unchanged, it breaks up 
in the intestine, liberating salicylic acid and acetylparamido- 
phenol, which is not toxic like the phenol set free from salol. 
Hence its action is akin to that of a mixture of salicylic acid and 
phenacetin. 

Salipyrin {antipyrin salicylate) is a white, crystalline powder 
without odor, but with a sweetish taste. It is sparingly soluble 
in water, alcohol, and ether. It is prepared by direct union of 
salicylic acid and antipyrin, and is an antirheumatic and analgesic. 

Dose: 15 gr. (1 gm.). 



47© CYCLIC COMPOUNDS 

Salicylsulphonic acid, C 6 H 3 (OH) .S0 3 H. COOH, is a crys- 
talline substance used in testing for albumose in urine (p. 615). It 
does not precipitate urates or resins, but throws out all proteins. 
None of the proteins precipitated redissolves on heating except 
albumose. 

Gallic acid (C 6 H 2 (OH) 3 COOH) (trihydroxy '-benzoic acid) is 
found in tea, nutgalls, and other astringent vegetable products. 
It is prepared by boiling tannic acid with dilute acids, so as to 
hydrolyze it: 

C 14 H 10 O 9 + H 2 = 2C 7 H 6 5 

Tannic acid. Gallic acid. 

It is a white, crystalline solid, melting at 215 ° C. (419 ° F.) to 
form pyrogallic acid and carbon dioxid. It is soluble in water, 
imparting an acid reaction and an astringent taste. It is a reduc- 
ing agent, precipitating metallic gold, silver, and platinum from 
solutions of their salts. With ferric chlorid it gives a bluish- 
black precipitate. A deep rose color develops when its solution 
is treated with a piece of potassium cyanid. 

Dose: 5 to 20 gr. (0.3-1.25 gm.). It is incompatible with 
ammonia, lead acetate, opium, silver salts, ferric salts, potassium 
chlorate, and permanganate. 

Tannic acid (C 14 H 10 O 9 =(C 6 H 2 ) 2 . (OH) 5 . CO . COOH) (tan- 
nin, digallic acid) occurs in tea leaves, in the bark of trees, and 
in large amounts in nutgalls, from which it is obtained by extrac- 
tion with boiling water, alcohol, or ether. It is usually prepared 
in light-yellow, amorphous scales which have a very astringent 
taste and characteristic odor. It is easily soluble in water, giving 
an acid reaction, and with ferric chlorid a blue-black or dark-green 
color. The fact that hydrolysis converts it completely into gallic 
acid shows that it is an anhydrid of that acid. 

Tanning is the art of making leather from prepared animal 
skins or membrane by immersion in a solution of tannic acid or 
a mixture of astringent bark. The animal substance absorbs and 
combines with the tannin, changing to the tougher leather, which 
does not putrefy. 

In medicine tannic acid is valued as an astringent and styptic. 
Dose: 2 to 10 gr. (0.13-0.6 gm.). It is present in the prepara- 
tions: glycerite (20 per cent.); styptic collodion (20 per cent.); 
ointment (20 per cent.); troches (1 gr. each). 

Its incompatibles are the salts of iron, lead, mercury, antimony, 
copper, and silver; alkaloids, gelatin, albumin, starch, iodin, 
iodoform, lime water, spirits nitrous ether, chlorates, and per- 
manganates. 



POLYNUCLEATED COMPOUNDS 47 I 

Tests. — Ferric chlorid gives a deep blue precipitate which 
redissolves in excess, changing to a green color. Potassium 
hydroxid yields with it a brown color. A weak solution of tannic 
acid, treated gradually with lime-water, precipitates white, chang- 
ing to blue and green. 



POLYNUCLEATED COMPOUNDS 

The compounds hitherto studied have but one benzene nucleus 
or closed chain of 6 carbon atoms. They may be regarded as 
simple derivatives of benzene, being easily prepared from it and 
reconverted to it. There are others, however, which are also 
derivatives of benzene, but which are in a class of aromatic hydro- 
carbons containing two independent closed chains joined at one 
point, like diphenyl, or even three, like triphenyl-methane. 



Diphenyl. 

In the fatty series ethane, C 2 H 6 , is sometimes considered as 
having 2 methyl groups, CH 3 . CH 3 , and called dimethyl. So it 
is that phenyl, C 6 H 5 , uniting directly with another phenyl group, 
forms the hydrocarbon diphenyl, C 6 H 5 — C 6 H 5 , which is not, how- 
ever, a homologue of benzene. This and other hydrocarbons, 
such as naphthalene and anthracene, form the starting-points of 
new homologous series, and become the parents of a large number 
of derivatives. 

Diphenyl, C C H 5 — C 6 H 5 , is prepared by removing with sodium 
the bromin of brombenzene in ethereal solution: 

2 C 6 H 5 Br + 2Na = C 6 H 5 . C 6 H 5 + -2NaBr. 

It is a colorless crystalline substance, which when oxidized 
forms benzoic acid with destruction of 1 benzene nucleus. It 
forms a whole class of substitution derivatives, of which one is 
diphenylamin. This, dissolved in strong sulphuric acid, is a deli- 
cate test for nitric acid, turning blue with a trace of acid or nitrate. 

Naphthalene, C 10 H 8 (naphthalin), is second only to benzene 
in its economic importance. Like anthracene, it is the point from 
which dyemakers start in the production of a large number of 



472 CYCLIC COMPOUNDS 

valuable colors. It is more abundant in coal-tar than any other 
hydrocarbon. Its crude crystals are deposited on cooling the 
fractional distillate of coal-tar, boiling between 180 and 220 C. 
(356 ° and 428 ° F.). The impurities are made non-volatile by 
the addition of sulphuric acid, the pure volatile naphthalene being 
then separated by sublimation. 

It forms in large, colorless, lustrous plates, melting at 80 ° C. 
(176 ° F.) and boiling at 218 C. (424 F.). It is extremely vola- 
tile at all temperatures, giving off a penetrating, peculiar, but not 
ill-smelling vapor. This vapor mixed with coal-gas gives increased 
illuminating power. Almost insoluble in water, it dissolves easily 
in hot alcohol and ether. It is largely used under the names of 
moth balls, white tar, and mineral camphor, to prevent the destruc- 
tion of wool and fur clothing by moths. Its chief use is in making 
the naphthalene dyes. 

It is used in medicine as an antiseptic and parasiticide. Dose: 
5 to 10 gr. (0.3-0.6 gm.). 

Toxicology. — Given to lower animals, naphthalene causes diar- 
rhea and wasting, with cataract and other changes in the eye. 

Symptoms. — Poisonous doses are followed by distress of the 
stomach, vomiting, colic, and purging. Eliminated by the kid- 
neys, it causes pain in the back and over the bladder, with albu- 
minous and dark-colored urine. 

Tests. — Naphthalene is dissolved out of a distillate by means 
of ether. Picric acid yields with it yellow crystals. A fragment 
dissolves in chloral without change of color, after warming on a 
water-bath. On adding to this a few drops of hydrochloric acid 
and warming, the mixture turns to a rose color, changing to violet 
or brown on the addition of zinc. 

Constitutional Formula. — All the experiments to ascertain 
the structure of the naphthalene molecule, C 10 H 8 , point to the con- 
clusion that it and its derivatives are best explained when its 
constitution is expressed by two closed chains of 6 carbon atoms, 
so condensed that they have 2 carbon atoms in common, as shown 
by the double hexagon below: 



or simply 



CH 

HC \ A 

CH 

Naphthalene. 


CH 


CH 
CiqH«. 




a a 

Alpha and beta positions. 



To account for 2 isomeric monosubstitution products of naph- 
thalene, use is made of the fact that the 8 hydrogen atoms have 
not all the same relations to the rest of the molecule. For ex- 



NAPHTHOL 



473 



ample, the four a positions are identical, so are the four ,3 posi- 
tions; but the one set differs relatively from the other. This 
accords with the fact that there are 2 monochlornaphthalenes, 
2 monohydroxynaphthalenes, etc. At any angle marked a the 
substituting atom is in union with a carbon atom common to 
both hexagons, while those marked /9 are not so placed. 

Naphthol (C 10 H 7 OH). — The two monohydroxy-substitution 
derivatives of naphthalene are known as alpha-naphthol and beta- 
naphthol. Their constitution is shown by the duplicated rings: 
OH 





a-Naphthol. 0-NaphthoI. 

These correspond with monohydric phenols and are of great 
importance in dye-making. They are both derived from coal-tar 
or naphthalene, and have color reactions with ferric chlorid and 
behave in other ways like the phenols. Both are colorless and 
crystalline, with a faint odor recalling that of carbolic acid, and a 
burning and acrid taste. Beta-naphthol is readily soluble in hot 
water, which is not the case with alpha-naphthol. Betanaph- 
tholum, U. S. P., is an intestinal antiseptic and parasiticide. Dose: 
5 to 10 gr. (0.3-0.6 gm.). 

The hydrogen of the hydroxyl may be replaced by metals, 
giving rise to a class of naphtholates, such as that of bismuth and 
that of sodium, C 10 H 7 ONa (microcidin). 

Experiment. — Molisch's Test for Sugars. — If a carbohydrate 
in solution be treated with an alcoholic solution of a-naphthol and 
a few drops of sulphuric acid added carefully to form a bottom 
layer, a violet band due to furfurol appears at the line of contact. 
This reaction reveals sugar even when in combination with proteins, 
as in glucosamin. 

Toxicology. — At one time beta-naphthol was used as an alco- 
holic solution or ointment, applied to the skin to cure scabies. 
After such applications there have been in some cases eczema, 
retinal changes, acute nephritis, and death. One dram (3-4 gm.) 
in the form of ointment was fatal to a pregnant woman in twenty- 
five hours. 

Treatment. — The symptoms call for the same procedures as 
are used for phenol-poisoning (p. 456). 

Detection. — The suspected material is shaken with alcohol and 
the extract evaporated to a residue. This, warmed with potassium 
hydroxid and chloroform, yields a blue color. 

Aluminium naphthol-disulphonate (alumnol) is a salt of the 



474 CYCLIC COMPOUNDS 

dibasic acid, C 10 H G (OH)(SO 3 H) 2 , derived from naphthol by the 
action of sulphuric acid. Naphthosalol is salicylate of /3-naphthol 
or betol. 

Anthracene (C 14 H 10 ). — As the starting-point in the synthesis 
of alizarin {artificial madder) and turkey-red dye, anthracene is 
prepared extensively from the green oil of coal-tar. It crystal- 
lizes in colorless, lustrous, fluorescent plates, soluble in hot ben- 
zene. 

Constitutional Formula. — There is evidence that the molecule 
of anthracene is composed of condensed nuclei, and experience 
shows that the facts can be accounted for if its constitution be 
regarded as consisting of 2 benzene residues linked by 2 CH 
groups or 3 hexagonal rings. Thus: 

CH CH CH 

/C h x Hq/^\ C /\ CH 

c « h <cJh> C6H4 



hc 



CH 



'C\^C 
CH CH CH 



Phenanthrene (C 14 H 10 ). — Coal-tar yields this isomer of an- 
thracene. It appears to be diphenyl in which the 2 benzene 
residues are united at the ortho-positions by the group — HC:CH — 
thus: H 4 C 6 -HC:CH-C 6 H 4 . It is formed as a condensation product 
after the vapor of benzene compounds has passed through a red- 
hot tube. It is found as a nucleus in the alkaloids morphin and 
codein. 

CO 
Anthraquinon (C 6 H 4 < ro >C 6 H 4 ) (Diphenylene-diketone). — 

When anthracene is treated with nitric acid it does not yield a 

nitro-derivative: it is oxidized to anthraquinon, C 14 H 8 2 , 2 atoms 

of hydrogen being displaced by 2 atoms of oxygen. 

It crystallizes in yellow needles, and when acted on by 

sulphuric acid and then by soda and potassium chlorate 

yields, by complex processes, alizarin or dihydroxyanthraquinon, 

CO 
C 6 H 4 <p^>C 6 H 2 (OH) 2 . This is the active color principle of 

the madder root. It produces various colored compounds with 

metallic oxids; for example, with aluminium, a fast red, turkey 

red; with lime, blue; with a ferric salt, dark purple. 

Alizarin monosodium sulphonate is the yellow reagent used by 

Topfer as an indicator for uncombined acids of the gastric juice, 

excess of caustic soda turning the tested fluid pure violet by the 

CO 
formation of the disodium derivative, C 6 H 4 <pQ>C 6 H 2 (ONa) 2 

(Plate 6, B, B'). 



NITROBENZENE 475 

NITROGEN DERIVATIVES OF BENZENE 

An important class of compounds results from the ease with 
which nitro- (N0 2 ), amido- (NH 2 ), and diazo- (N 2 ) groups are sub- 
stituted for the hydrogen of the benzene nucleus. The nitration 
of many aromatic compounds is accomplished by solution in nitric' 
acid. When not soluble in nitric acid, the process is facilitated by 
using a mixture of strong nitric and sulphuric acids. As a rule, a 
high temperature and concentrated acids cause the substitution of 
several nitro-groups. Generally speaking, the nitro-compounds are 
crystalline and yellowish, insoluble in water, but soluble in benzene, 
ether, and alcohol. 

Nitrobenzene (C 6 H 5 .N0 2 ) (Essence of Mirbane).— When 
benzene (10 c.c.) is slowly treated with a mixture of nitric acid 
(12 c.c.) and sulphuric acid (16 c.c), and the vessel kept cool by 
immersion in water, the benzene dissolves. When poured into 
water a yellow oil sinks to the bottom. This is nitrobenzene, and 
the reaction is as follows: 

C 6 H 6 + HNO3 = C 6 H 5 N0 2 + H 2 0. 

Nitrobenzene is insoluble in water, has a specific gravity of 1.2, 
is sweetish in taste, and has a strong odor, resembling oil of bitter 
almond, for which oil it is often substituted in flavors and perfumes, 
notwithstanding its poisonous character. Its chief use is in the 
manufacture of anilin. 

Toxicology. — It breaks down the blood-corpuscles, forms meth- 
emoglobin (Plate 4, Fig. 1, d), and paralyzes the nerve centers. 
The immediate symptoms may not be noticeable for several 
hours, when suddenly the face becomes livid, the nails bluish, 
the pulse feeble, the skin cold; giddiness and vomiting may lead 
quickly to coma, sometimes complicated with convulsions, and 
often ending in death from apnea. If death is not prompt, the 
case may be complicated by jaundice. The same symptoms, 
resembling those caused by hydrocyanic acid, have been induced 
by inhalation of the vapor in the industries using nitrobenzene. 

Fatal Dose and Period. — Death would probably be caused by 
30 drops to 1 dram. Coma usually appears in four hours, with 
death two hours later. 

Treatment. — Using a siphon tube, the stomach should be washed 
out with warm water freely. Strychnin, digitalis, and artificial res- 
piration are useful to sustain the heart and respiration. Alcohol 
by the stomach must be avoided, as it favors absorption. 

Postmortem Appearances. — These include a persistent odor of 
bitter almond and oily drops of the nitrobenzene in the alimentary 
tract. The blood is chocolate-colored and fluid. 



476 CYCLIC COMPOUNDS 

Detection. — (i) Nitrobenzene is dissolved in warm alcohol and 
reduced to anilin by adding powdered zinc, followed by single 
drops of hydrochloric acid to evolve hydrogen until no odor of 
nitrobenzene is left. The solution, diluted and made alkaline, is, 
extracted with ether and the residue tested for anilin (p. 478). 

(2) A few grains of potassium hydroxid mixed with 3 drops of 
water and 2 drops of carbolic acid are boiled in a dish and then a 
few drops of the suspected material is added. After boiling, a 
red ring appears at the edge, the red changing to green when 
calcium hypochlorite is added. 

AROMATIC AMIDO-COMPOUNDS AND AMINS 

In another place (p. 494) the amids and amins of the fatty 
series are referred to as ammonia, in which the hydrogen atoms 
have been displaced by fatty radicals. Analogous compounds 
are made when the radicals substituted are aromatic, such as 
amidobenzene, C 6 H 5 . NH 2 , and benzylamin, C 6 H 5 . CH 2 . NH 2 . 
Those which, like amidobenzene, have the amido-group united 
directly with the nucleus are called amido-compounds; those 
containing that group in the side chain, like benzylamin, are 
called aromatic amins, and are of very little importance. 

Preparation of amido=COmpOUnds in general is performed by 
reducing the nitro-compounds with nascent hydrogen, a metal,. 
or stannous chlorid. Thus: 

C 6 H 5 N0 2 + 6H = C 6 H 5 .NH 2 + 2 H 2 0. 

Nitrobenzene. Amidobenzene. 

The properties of the amido-compounds are similar to those 
of the primary amins. The basic character of ammonia is dimin- 
ished by the substitution of phenyl, C 6 H 5 — , which is not the case 
with the fatty amins. Warmed with nitrous acid in solution, they 
yield phenols, as the fatty amins under like conditions form alcohols: 

C 6 H 5 . NH 2 + HN0 2 = C 6 H 5 . OH + N 2 + H 2 0. 

Amidobenzene. Nitrous acid. Phenol. 

Anilin (C 6 H 5 . NH 2 ) (Amidobenzene, Phenylamin). — Anilin is 
contained in coal-tar in small quantities, but com- 
y^" 2 mercially it is prepared by reducing nitrobenzene 
HO, ^CH w i tn nascent hydrogen. 

|| I When pure, it is a colorless, oily, neutral liquid, 

\/^ w * tn a f a i nt > peculiar odor and a bitter taste. Spar- 

CH ingly soluble in water, it dissolves readily in alco- 

hol and ether. Exposed to light it darkens. It 
acts as a base, neutralizing acids and forming salts, such as anilin 
hydrochlorid, C 6 H 5 . NH 2 HC1. 



AROMATIC AMIDO -COMPOUNDS AND AMINS 477 

A mixture of chloroform and alcoholic potash heated with one 
drop of anilin gives the offensive vapor of isobenzonitril, C 6 H 5 . NC. 
By oxidizing agents, such as arsenic acid, it is converted into 
rosanilin, from which derivatives of various colors are easily 
produced. This is the basis of the large industry of dye-making. 
Rosanilin chlorid, C 20 H 20 N 3 C1, forms crystals of a green, metallic 
luster, which dissolve in warm water to form a deep red solution 
that dyes fabrics a brilliant magenta. The identity in color of the 
nitrate and other salts finds explanation in the same colored ion. 
If the ion be changed by the introduction of methyl for hydrogen, 
the changes in color range through violet to blue, according to the 
number of methyl groups. 

Pyoktannin-blue is pentamethylrosanilin chlorid, violet in color, 
soluble, and used as an antiseptic. Methyl-blue is the sodium 
sulphonate of triphenylrosanilin. It is used locally as a disin- 
fectant, but internally is poisonous, having caused death by mis- 
take for methylene-blue, which is less active. 

Methylene-blue (methylthionince hydrochloridum, U. S. P.), is 
formed by the action of hydrogen sulphid upon an oxidation product 
of para-amido-dimethylanilin. It occurs in dark green, bronze-like 
crystals which readily make a deep blue aqueous solution. It is 
used in dyeing, staining bacteriologic specimens, and internally 
is given for its analgesic and antipyretic effects. Dose: i to 3 gr. 
(0.065-0.2 gm.). 

Toxicology. — Cases of poisoning are found in dye-workers who 
inhale the vapors, but others wearing socks and boots dyed with 
anilin colors have suffered from absorption by the skin. Like 
nitrobenzene, it breaks down the blood and paralyzes the nerve 
centers. The methemoglobin in the blood imparts a bluish color 
to the face and finger-nails. The gait is unsteady, the head aches 
and is dizzy, the pulse feeble, and drowsiness ends in coma. 
Chronic poisoning causes eczema, anemia, and amblyopia. Anilin 
is oxidized in the system to para-amidophenol, C 6 H 4 . OH . NH 2 , 
which is eliminated as a conjugate sulphate. From this the 
urine takes a dark color and reduces Fehling's solution like glucose. 
The U. S. Board of Food Inspection (1908) forbids the use in 
food of any coal-tar dye except those known in commerce as 
amaranth and erythrosin red; orange I; naphthol yellow S; light 
green S. F., yellowish; and indigo disulphacid. 

Fatal Dose and Period. — Death is probable within twenty hours 
after doses of 1 fl. oz. (30 c.c). 

Treatment. — When the poison has been inhaled, fresh air and 
stimulants are called for; if swallowed, evacuation of the stomach 
and bowels, followed by stimulants. 

Postmortem Appearances. — There is an odor of coal-tar or anilin 



478 CYCLIC COMPOUNDS 

in the body, with a brownish color of the blood, due to meth- 
emoglobin (Plate 4, Fig. 1, d). 

Detection. — 1. A solution of free anilin is turned violet by a few 
drops of fresh calcium hypochlorite. If this be pale, a few drops of 
ammonium sulphid develops a visible rose color. 

2. Sulphuric acid with a trace of anilin turns slowly blue or 
green when treated with potassium dichromate. The same 
reagents with strychnin yield a blue, changing to purple and red. 

3. One drop of anilin yields with chloroform and alcoholic potash 
the isobenzonitril odor (p. 388). 

Acetanilid (C 6 H. . NH . C 2 H s O) (Antijebrin, Phenyl -acetanilid). 
— When the hydrogen of the amido-group in 
CNHC 2 H 3 anilin is replaced by acid radicals, the derivative 
is called anilid; for example, acetanilid, form- 



tir'/ VvpfT 

i; r anilid, and oxanilid are anilids prepared by the 

HCv ^/CH action of the corresponding acids. When the 

£tt hydrogen atom is displaced by an alkyl radical, 

the derivative is known as an alkylanilin; for 

example, methylanilin, C 6 H 5 . NH . CH 3 . 

Preparation. — Acetanilid is prepared by boiling anilin with 
glacial acetic acid. Anilin acetate is formed and slowly changes, 
during prolonged boiling, to acetanilid and water. Distillation 
purifies the acetanilid, which is collected and crystallized in lus- 
trous white plates having a burning taste. It is odorless and is 
greasy to the touch. 

C 6 H 5 .NH 2 + CH3.COOH = C 6 H 5 . NH . C 2 H 3 + H 2 0. 

Anilin. Acetic acid. Acetanilid. 

Properties. — Acetanilid melts at 113 C. (235 ° F.). It dis- 
solves sparingly in cold water, but freely in hot water, alcohol, and 
ether. When heated with acids or alkalis it takes up water, yield- 
ing anilin and acetic acid. Its solutions are neutral and are 
unaltered in color by either ferric chlorid or sulphuric acid. 

Acetanilid is anodyne, antiseptic, antipyretic, and antirheumatic. 
It is the basis of many "headache powders." Pulvis acetanilidi 
compositus contains in 10 gr. : acetanilid, 7 gr.; caffein, 1 gr.; sodium 
bicarbonate, 2 gr. 

Dose: 2 to 10 gr. (0.13-0.6 gm.). It is incompatible with 
alkaline bromids or iodids, forming compounds insoluble in 
water. It causes spirits of nitrous ether to turn yellow and red. 
Rubbed with chloral or carbolic acid it forms a soft mass. 

Toxicology. — Many cases of poisoning are attributable to the 
three anilin derivatives — acetanilid, exalgin, and phenacetin — taken 
carelessly as antipyretics and anodynes. The lowered temperature 

NH 

results from the amidophenol, C 6 H 4 < tt 2 , formed in the tissues 



AROMATIC AMIDO-COMPOUNDS AND AMINS 479 

by oxidation of the amidobenzene group, and which is excreted as a 
sulphate. All of them cause methemoglobin to appear in the blood 
(Plate 4, Fig. i, d), producing cyanosis, muscular weakness, dark 
or bloody urine, nephritis, and jaundice. Very large doses cause 
sudden profuse perspiration, dizziness, collapse, dyspnea, coma, 
and convulsions. Chronic poisoning from abuse of "headache 
powder" is characterized by cyanosis, dyspnea, weakness, dys- 
pepsia, anemia, wasting, and dark-colored urine. 

Fatal Dose of Acetanilid. — In cases of weak heart or typhoid 
fever small doses of 10 to 30 gr. (0.6-2 gm.) may cause alarming 
symptoms. Death has followed 60 gr. 

Treatment. — Besides clearing out the stomach and bowels, there 
is an immediate indication for hypodermic doses of strychnin, 
followed by normal salt solution. 

Detection. — 1. Indophenol Reaction. A gram of acetanilid boiled 
with 2 c.c. of strong hydrochloric acid and cooled is treated with 
2 c.c. of the saturated solution of phenol and a few drops of 
calcium hypochlorite or chlorin water. The red color thus formed 
is altered by addition of ammonia to a blue. This test identifies 
the amidophenol in the urine if performed by the following method: 
The urine, concentrated on a water-bath, is boiled for three minutes 
with one-tenth its volume of hydrochloric acid to set free the 
amidophenol from sulphuric acid. After cooling it is shaken 
with an equal volume of ether, which is separated and evaporated. 
The residue, dissolved in water, is treated with a few drops of 
solution of phenol and some solution of chlorinated lime. The 
amidophenol first formed gives a red color of indophenol with 
the phenol and chlorin, which ammonia changes to blue. 

2. Heated with chloroform and alcoholic potash, the isobenzo- 
nitril odor is developed (p. 388). 

Methylacetanilid (C 6 H 5 . N . CH 3 . C 2 H 3 0) (Exalgin).— By the 
action of methyl iodid upon sodium acetanilid 
the methyl group is substituted for an atom of ^NCH 3 .C 2 H 3 
hydrogen in acetanilid. Methylacetanilid is crys- 
talline, tasteless, faintly aromatic, sparingly sol- 
uble in water, freely in alcohol. It is antipyretic 
and analgesic. Exd^n. 

Dose: 4 to 7 gr. (0.25-0.4 gm.). 

Phenacetin (C 6 H 4 . C 2 H 5 . O . NHC 2 H 3 0) (Acetphenetidin, 
Oxyethylacetanilid) . — The effect of reducing C NH C H O 

agents upon a nitrophenol, C 6 H 4 . OH . N0 2 is to /\ 
form the related amidophenol, C 6 H 4 . OH . NH 2 . HGj ^,CH 
When ethyl is substituted for the hydrogen of pjjl l CH 

the — OH, a corresponding ethylic ether or phe- \^s 
netidin is the result, C 6 H 4 . 0(C 2 H 5 ) . NH 2 . When CO.C 2 H 5 




480 CYCLIC COMPOUNDS 

paraphenetidin is treated with glacial acetic acid, the acetyl group, 
C 2 H s O — , is substituted for 1 atom of hydrogen in the — NH 2 , and 
the product is acetphenetidinum (U. S. P.). 

Its composition differs from that of acetanilid in having oxy- 
ethyl, — O . C 2 H 5 , introduced in place of an atom of hydrogen in 
the nucleus. 

It is extensively used as an antipyretic, analgesic, and anti- 
neuralgic, under the name phenacetin. It is a white, odorless, 
tasteless, crystalline powder, sparingly soluble in water, readily so 
in alcohol. Cases of poisoning have occurred from overdoses, 
though it is a safer medicine than acetanilid. The symptoms and 
treatment are the same as those of acetanilid. 

1. Nitric Acid Test. — With a few drops of concentrated nitric 
acid phenacetin yields a yellow to orange-red color. Heat com- 
pletes the solution, which on cooling gives crystals of nitrophen- 
acetin. 

2. Indophenol Test. — The same reaction as that of acetanilid, 
given above. Three per cent, chromic acid may be substituted for 
the calcium hypochlorite. 

Dose: 5 to 15 gr. (0.3-1 gm.). Its incompatibles are chloral, 
carbolic acid, iodin, salicylic, chromic, and nitric acids. 

Methacetin [C 6 H 4 . OCH 3 . NH(C 2 H 3 0)] (Oxymethacetanilid). 
— The methyl ether of an amidophenol is known as an anisidin, 
C 6 H 4 . OCH3 . NH 2 . Acted on by glacial acetic acid, this forms 
methacetin by the substitution of oxymethyl for an atom of hydro- 
gen in the nucleus. ♦ 

This substance crystallizes in white, odorless, and tasteless 
lustrous scales, sparingly soluble in water, readily so in alcohol. It 
is used as an antipyretic and analgesic. '*■ 

Dose: 3 to 8 gr. (0.2-0.5 gm.). 

DIAZO-COMPOUNDS 

When anilin hydrochlorid in very cold, Solution is mixed with 
sodium nitrite, and then, by the addition of hydrochloric acid, 
nitrous acid is liberated in the mixture; a reaction takes place with 
the formation of diazobenzene chlorid: 

C 6 H 5 .NH 2 .HC1 + HN0 2 = C 6 H^£T 2 C1 + 2HO. 

Anilin hydrochlorid. Diazobenzene chlorid. 

v T 

The term diazo refers to the 2 atoms 01 nitrogen linkipg the 
phenyl radical to other components: R — N 2 — . When the free 
bond is united to acid groups or halogens, the products are called 
diazo salts: C 6 H 5 . N 2 . S0 4 H is diazobenzene sulphate. They 



PLATE 3. 




Phenylhydrazin Test for Sugars. 



In a test tube put nearly y z in. (1 gm.) of phenylhydrazin hydrochloric!, an equal 
quantity of powdered sodium acetate, and enough of the suspected fluid to half-fill 
the tube. The acetate dissolves as the tube is heated. Boil for 2 minutes and 
examine after 20 minutes, or, if hurried, examine a drop under the microscope at once 
without a cover-glass. In 2 or 3 minutes the crystals form : «, Sheaves and stars of 
needles — glucosazone ; b, rosettes of lance-shaped crystals — maltosazone ; c, spicules 
in burr-like clusters — lactosazone. 




DIAZO-COMPOUNDS 48 1 

may be regarded as compounds of hypothetic 
diazobenzene, C 6 H 5 . N 2 . OH, and its derivatives. 
These salts, when dry, are unstable to the degree 
of being explosive. They are colorless, crystal- 
line, anoVvery soluble in water. Their value in' . 

. , , . . r Diazobenzene 

industrial chemistry is very great, as they furnish sulphate. 

a mother substance susceptible to many reactions, 

producing a large class of dye substances of varying colors. 

When one bond of each of the 2 nitrogen atoms is united to an 
atom of hydrogen, a hydrazo-com-pound is formed. 

Phenylhydrazin (C 6 H 5 . HN . NH 2 ).— This important sub- 
stance can be prepared by reducing diazobenzene with hydro- 
gen: 
& C . HN . NH 2 

C 6 H 5 .N 2 C1 + 4 H = C 6 H 5 . NH . NH 2 . HC1 /\, 

Diazobenzene chlorid. Phenylhydrazin hydrochlorid. \\ iCH 

From the hydrochlorid the free base, phenyl- Hc \ J /Cil 
hydrazin, is liberated by potash. Hydrazin, qh 

or diamin, is the name given to the group H 2 N — 
NH 2 , from which it is assumed these reduction products are derived. 

Phenylhydrazin is a crystalline, sparingly soluble, strong base, 
forming salts with acids. Both base and salts reduce Fehling's 
solution in the cold. It reacts with aldehyds and ketones to form 
hydrazones, and with grape-, milk-, and malt-sugars to form osa- 
zones. Cane-sugar does not yield an osazone. As these sub- 
stances are usually crystalline solids of difficult solubility, they 
are often formed in tests for identifying and isolating aldehyds 
and sugars. The osazones are separated as crystals from aque- 
ous solutions of sugars by boiling with excess of phenylhydrazin 
hydrochlorid and sodium acetate (Plate 3, a, b, c). 

Phenylhydrazin hydrochlorid is a white, changing to a fawn- 
colored, crystalline powder, with an agreeable odor. It decomposes 
readily into a dark, offensive paste, which is no longer suitable as a 
reagent for sugar testing. The crystalline powder should not be 
permitted to touch the skin, as it may cause an annoying eruption. 

Another interesting use of phenylhydrazin is in the manufacture 
of antipyrin. 

Antipyrin (C 6 H 5 . (CH 3 ) 2 . N 2 C 3 OH) (Phenyl-dimethyl-pyrazolon, 
Phenazone). — This is a synthetic base, a _ TT ■ _ __ _ „ u ru 

j . .. ' , 11. j • r j • CH0.N.N.C3OH.CH3 

derivative of phenylhydrazin, not found in 
nature, and hence sometimes called an arti- 
ficial alkaloid. It is prepared by treating 
diacetic ether with phenylhydrazin, making 
phenyl-methyl-pyrazolon; and then intro- 
ducing a second methyl group by heating with methyl iodid. 
31 




482 CYCLIC COMPOUNDS 

It is a white, odorless, bitter, crystalline powder, readily soluble 
in water and alcohol. It fuses at 113 C. (235 ° F.) and is strongly 
basic, formiiM^soluble salts. With ferric chlorid it yields a deep 
red color, and with nitrous acid a bluish green color. 

In medicine it is used locally as a styptic and internally as an anti- 
pyretic, antirheumatic, and analgesic. Dose: 5 to 15 gr. (0.3-1 
gm.). It has many incompatibles: the halogens, ammonia water, 
sodium bicarbonate and salicylate, chloral, copper sulphate, 
chromic acid, iodids, lead subacetate, calomel, mercuric chlorid, 
alum, carbolic acid, amyl nitrite, benzoates, beta-naphthol, spirits of 
nitrous ether, quinin, ferric chlorid, tartar emetic, tannic acid, and 
vegetable astringents. 

Toxicology. — Poisoning from antipyrin is nearly always due to 
the free use of it as a medicine in cases many of which were unfit 
for it because of defective heart or kidneys. 

Acute cases show feeble pulse, difficult breathing, and cyanosis, 
not so great as that caused by acetanilid. Muscular tremblings 
may be associated with the stupor, collapse, and coma. 

Chronic poisoning from habitual use causes edema of the face, 
cutaneous affections, indigestion, mental dulness, and anemia. 

Fatal Dose. — In patients having heart or lung diseases 20 gr. 
would be dangerous. 

Treatment. — The patient is placed in the supine position and air 
or oxygen is supplied freely. The stomach is evacuated by emetics 
or the siphon tube. Ammonia may be inhaled and hypodermic 
injections given of whisky or strychnin. 

Tests. — 1. Nitrous acid liberated from a solution of potassium 
nitrite by sulphuric acid causes with an aqueous solution of anti- 
pyrin a blue-green nitroso-antipyrin. 

2. Ferric chlorid gives a red color with antipyrin, like that pro- 
duced with diacetic acid (Plate 8, Fig. 6). The color disappears 
by the action of mineral acids. 

3. Fuming nitric acid, two drops, added to a few drops of solution 
of antipyrin, gives a green color. After heating this to boiling 
another drop of the acid produces a red color. 

Saccharin (C 6 H 4 CO . S0 2 NH) {Benzoic Sulphinid, Benzoylsul- 
phonic I mid). — In making this substance 0-sulphobenzoic acid is 
first prepared, and this, treated with ammonia, yields the imid: 

C.H 4 <|5xJ2 + NH S = C 6 H 4 <^>NH + 2 H 2 0. 

Sulphobenzoic acid. Saccharin. 

It is a white powder with a slight aromatic odor and a remarkably 
sweet taste, being nearly 300 times as sweet as cane-sugar. It is 
sparingly soluble in water, but freely so in ether and alcohol. Its 



PYRIDIN AND ITS DERIVATIVES 483 

solubility is increased by alkaline carbonates, which convert it to 
soluble saccharin. 

Experiment. — Its presence is detected by acidulating with sul- 
phuric acid the sugar or other suspected substance and shaking 
with ether, which does not dissolve sugar, but extracts the saccharin. 
On separation and evaporation the residue of saccharin is crys- 
talline and sweet. 

Uses. — It is used to disguise the taste of unpalatable medicines, 
and as a substitute for sugar in diabetes, obesity, and gout. 

Toxicology. — It retards the action of the enzyms in the digestive 
fluids and also those of the blood and tissues. To a certain extent 
it depresses general metabolism. 

Benzidin (NH 2 . C 6 H 4 . C 6 H 4 . NH 2 ) {p-Diamidodiphenyl) .— This 
may be compared with two molecules of anilin. It is made by 
the action of acids, causing an intramolecular rearrangement in 
Jiydrazobenzene, C 6 H 5 . NH . NH . C 6 H 5 . It occurs in colorless, 
shining plates, is strongly basic, and is used in the preparation 
of azo-dyes such as congo-red, whose sodium salt is a scarlet 
powder which is turned blue by acids. Benzidin is used in a 
delicate test for blood (p. 617). 



HETEROCYCLIC COMPOUNDS 

The cyclic compounds previously described have 6 carbon atoms 
in the ring. As the atoms at the angles are alike, they are called 
isocyclic. If a ring contains fewer than 6 carbon atoms, it is 
irregular and the compound is called heterocyclic. One of the C 
atoms may be replaced by N, as in pyridin, or the ring may have 
only 4 C atoms with NH, as in pyrrole. 

CH CH 



Hc/\ 




jCH HGj ^CH HGt ijCH 

JcH HC JcH Hol JcH 




CH N NH 

Benzene. Pyridin. Pyrrole. 

PYRIDIN AND ITS DERIVATIVES 

Among the constituents of coal-tar have been found certain 
aromatic bases allied to the alkaloids and known as pyridin bases. 
They were first discovered in bone oil, a dark brown liquid of dis- 
agreeable odor, formed when bones are heated in the preparation of 



484 CYCLIC COMPOUNDS 

boneblack. Purified by distillation, this bone oil was at one time 
used in medicine under the name of DippeVs oil. 

Pyridin, C 5 H 5 N, is a product of destructive distillation of many 
nitrogenous organic substances, and hence found in tobacco smoke. 
It is prepared by first making nicotinic acid, C 6 H 5 N0 2 , by oxid- 
izing nicotin. This, when distilled with lime, yields pyridin, as 
benzoic acid by the same process gives benzene: 

C 5 H 4 N.COOH = C 5 H 5 N + C0 2 . 

Nicotinic acid. Pyridin. 

Many considerations have established the opinion that pyridin, 
like benzene, has a closed chain or nucleus with trivalent nitrogen 
substituted for the trivalent group, CH=. Its constitution is repre- 
sented in the formula given above. 

Pyridin is a colorless liquid with a pungent, empyreumatic odor 
and sharp taste, freely miscible with water, alcohol, ether, and oils. 
Its specific gravity is 1.003, and its boiling-point 116 ° C. (241 F. ). 
It is a very stable substance of strongly basic properties, alkaline in 
reaction. It has been used in medicine as a respiratory sedative. 
Dose: 2 to 10 drops. 

Piperidein (C 5 H 5 NH). — By the action of nascent hydrogen on 
the pyridins the several carbon atoms take up additional hydrogen 
atoms, forming hydropyridins. The best known tetra-hydropyridin 
is the compound piperidein, of which the betel alkaloids are deriva- 
tives. 

Piperidin (C 5 H 10 NH) (Hexahydropyridiri).— When pyridin is 
dissolved in alcohol and treated with sodium, piperidin is formed as 
a reduction product: 

C 5 H 5 N + 6H = C 5 H 10 NH 

Pyridin. Piperidin. 

It is reconverted to pyridin on oxidation with sulphuric acid. 

It has been shown that the constitution of piperidin is repre- 
sented by the formula: 

CH 2 

H 2 C,/ \ch 2 

H 2 cl JcH 2 

NH 

Piperidin. 

The alkaloid piperin, found in pepper, yields piperidin when 
decomposed by boiling alkalis. Piperidin is a colorless liquid with 
an odor of pepper. It is miscible with water in all proportions, and 



PYRIDIN AND ITS DERIVATIVES 485 

is strongly basic. It behaves like a secondary amin, interacting 
with methyl iodid to form methylpiperidin, C 5 H 10 N . CH 3 . 

Piperidin and methylpiperidin are the nuclei of a number of 
vegetable alkaloids. Coniin, from hemlock, is a propylpiperidin; 
the tropin of atropin, and ecgonin of cocain, are derivatives of 
methylpiperidin (p. 507). 

The Pyridin Homologues. — These are the alkyl derivatives of 
pyridin: the isomeric picolins or methylpyridins, C 5 H 4 N . CH 3 ; the 
isomeric lutidins or dimethylpyridins, C 5 H 3 N(CH 3 ) 2 ; and the 
collidins or trimethylpyridins, C 5 H 2 N(CH 3 ) 3 . They are found in 
bone oil and coal-tar. 

HC=CH X 

Pyrrole, I /NH or C 4 H 5 N, is a constituent of bone oil. 

Hc=cir 

It is formed by varied reactions of organic nitrogenous substances, 
such as albumin and gelatin. It is a colorless liquid, smelling like 
chloroform and showing feebly basic properties. 

It has a homologous series which form substitution derivatives, 
among which is tetra-iodo-pyrrole, iodol, U. S. P., C 4 HI 4 N, a 
yellow-brown powder formed by ethereal solution of iodin acting on 
pyrrole in the presence of oxidizing agents. It is 89 per cent, iodin 
and is used in medicine as an alterative and antiseptic substitute for 
iodoform. It is odorless, tasteless, slightly soluble in water, freely 
in alcohol, chloroform, and oils. Dose: 8 to 15 gr. (0.5-1 gm.). 
H 2 C— CH 2 . 

Pyrrolidin, I /NH (tetrahydropyrrole) is made by the 

H 2 C — CH 2 
action of nascent hydrogen on pyrolle. It stands to pyrrole in 
the same relation that piperidin does to pyridin. An alkaline 
liquid, it resembles piperidin in its reaction. It is the nucleus of the 
hygrin alkaloids and one of the nuclei of nicotin (p. 505). 

Prolin or «=Pyrrolidin Carboxylic Acid.— This is produced by 
tryptic digestion or hydrolysis of casein. It pre-exists in casein as 
the dipeptid given below: 

g>CH.CH 2 CH.CO.N<^ c C ^ 
NH '= COOH 

The formula is that of a synthetic product of leucin and pyrrol- 
idin carboxylic acid, sometimes called leucylprolin. 

Piperazin (Hexahydropyrazin = Diethylenediamin). — When 2, 
3, or 4 nitrogen atoms are present in the benzene nucleus, the com- 
pounds are known as di-, tti-, and tetrazins. The diazins are three: 
orthc-, meta-, and para-, according to the positions of the nitrogen 



486 CYCLIC COMPOUNDS 

atoms. Each has a series of substitution derivatives. Paradiazin, 

CH . N . CH 

|i | II , is known under the name pyrazin. It is a by-product 

CH . N . CH • 

of alcoholic fermentation, and is found in fusel oil or commercial 

amyl alcohol. 

When 6 more hydrogen atoms are taken up by the disengaged 

CH 2 . NH . CH 2 
bonds, the substance is known as hexahydropyrazin, \ \ 

CH 2 . NH . CH 2 
or HN : (C 2 H 4 ) 2 : NH. This substance, called piperazin, may be 
prepared by reducing paradiazin. It is crystalline, colorless, sol- 
uble in water, deliquescent, strongly alkaline, and absorbs carbon 
dioxid from the air. It combines with uric acid to form piperazin 
urate, which dissolves in 50 parts of water. It is given as a solvent 
for uric acid, in the form of citrate and hydrochlorid. Dose: 8 gr. 
(0.5 gm.). It is best given alone, as it is incompatible with alum, 
copper sulphate, ferric chlorid, .potassium permanganate, silver 
nitrate, arsenic, and mercuric iodid, acetanilid, alkaloidal salts, 
carbolic acid, chloral hydrate, phenacetin, picric acid, quinin, so- 
dium salicylate, tannic acid, spirits nitrous ether. 

CO CO 

Indigotin (C 6 H 4 <^>C : C<^>C 6 H 4 ) (Indigo Blue).— 

This is the blue constituent of ordinary indigo formed from the 
yellow glucosid, indican, found in certain plants. By heating with 
dilute acids or by fermentation indican gives indigo blue. Several 
reactions produce it synthetically — that is, by oxidation of indoxyl 
or from cinnamic acid. 

Indoxyl sulphuric acid is a constituent of the urine, sometimes in 
such proportion that oxidizing agents give the urine a blue color 
from the formation of indigo. 

When indigo blue is oxidized, it is converted to isatin, which is 

yellowish brown. This property makes it useful as a test for nitric 

acid. It also loses its color by the action of reducing agents, as in 

the indigo test for glucose. 

NH 
Indol (C 6 H 4 <p-rr>CH) (Benzopyrrole). — This substance is a 

combination of the benzene and the pyrrole rings, as shown by 
the structural formula. It can be produced 
synthetically by several reactions. The most 
interesting method of formation is that by 
putrefaction of proteins in the intestines 
during digestion. Part of it remains in the 
fecal mass and part is absorbed and carried 
by the portal circulation to the liver to be 




PYRIDIN AND ITS DERIVATIVES 487 

oxidized to indoxyl, C 6 H 4 < Lu >CH. This readily combines 

with potassium sulphate to form potassium indoxylsulphate, 
C 6 H 4 . NH . CHKS0 4 . This is the indican or uroxanthin eliminated 
by the urine. It is not the glucosid referred to above, but an ether- 
eal salt or conjugate sulphate. 

When hydrochloric acid, with a trace of potassium chlorate or of 
ferric chlorid, is added to urine, this indican breaks up into potas- 
sium sulphate and indigo blue, the latter being formed by oxidation 
of the indoxyl: 

C 6 H 4 NH . CH . KS0 4 + H 2 = 

Indican. 

KHS0 4 + C 6 H 4 . NH . C(OH) . CH 

Indoxyl. 

2 (C 8 H 6 NOH) + 20 = C 16 H 10 N 2 O 2 + 2 H 2 0. 

Indoxyl. Indigo blue. 

This reaction is made use of in urinary analysis for indican by 
Jajje's method (p. 581). In testing for indican in the urine by this 
method the oxidation may be carried too far and the indigo blue be 
converted to yellowish isatin. 

The other conjugate sulphates found in the urine in traces are the 
potassium and sodium compounds of the ester-sulphuric acids of 
skatoxyl, phenol, catechol, quinol, and paracresol. They vary in 
amount inversely as the mineral sulphates; and after poisoning by 
carbolic acid all of the sulphuric acid is taken by the phenol com- 
pound at the expense of the mineral sulphates. 

Skatol (C 6 H 4 <^ H3) >CH) (,3-Methylindol).— Skatol is a 

methyl substitution of indol. The odor characterized as fecal is 
due to the presence of skatol with indol. The 
skatol exceeds the indol as a product of the 
putrefaction of proteins. It can be prepared 




by the reduction of indigo. Like indol, it is 
partly absorbed from the fecal mass in the 
intestines, and is excreted by the kidney as 
potassium skatoxylsulphate. 

Jaffe's test will yield a red or violet color when the skatoxyl com- 
pound is in excess. This color is called skatol red. Such urines, 
when oxidized by nitric acid, turn red, violet, and blue. 

Quinolin (C 9 H 7 N) (chinolin) is the parent substance of a group 
closely related to the vegetable alkaloids and known as the quinolin 
or benzopyridin bases. It is in coal-tar and bone oil, can be pre- 
pared by distilling quinin and cinchonin with potash, and syn- 





488 CYCLIC COMPOUNDS 

thetically by heating anilin, glycerin, and sulphuric acid in the 
presence of nitrobenzene. 

It is a colorless oil with a characteristic odor, sparingly soluble 
in water, forming crystalline salts with the acids. 

For various reasons the constitution of pyridin, C 5 H 5 N, and 
quinolin, C 9 H 7 N, is believed to have the same relation as that of 
benzene, C 6 H 6 , and naphthalin, C 10 H 8 , being represented by the 
formulas below, showing quinolin has a benzene and pyridin ring 
condensed: 

CH CH CH 

" J W 

Quinolin. 

Isoquinolin is very like quinolin in chemical properties, but dif- 
fers physically. It is found in coal-tar with quinolin. In consti- 
tution it differs from quinolin in that the benzene ring is attached by 
the /? and y positions, and not by the a and /?, as quinolin. 

Thallin (C 9 H 6 . O . CH 3 . N . H 4 or C 10 H U NO) (Tetrahydro- 
paramethyloxyquinolin). — Among the synthetic basic substances 
made from quinolin and containing its nucleus are thallin and 
kairin. Thallin receives its name from the intense green color it 
forms with ferric chlorid. Its sulphate is in yellowish needles, 
aromatic, bitter, and soluble in water. In medicine it is used as a 
transitory antipyretic and antiseptic. Dose: 2 gr. (0.13 gm.) 
hourly. 

PURINS AND URIC ACID 

Uric acid (C 5 H 4 N 4 3 ) (trioxypurin) occurs in the tissues of the 
body, the blood, and the human urine, in small amount, combined 
with sodium, potassium, ammonium, calcium, and magnesium. 
It is found as solid ammonium urate in the excrement of reptiles and 
birds. 

Preparation. — Having pulverized the excrement of a serpent, 
it should be boiled with sodium hydroxid in a porcelain dish until all 
the ammonia has been driven off. The liquid, having been filtered 
while hot, is poured into hydrochloric acid. As it cools, a fine crys- 
talline powder of uric acid falls (Plate 7, Fig. 5). 

It can be prepared by synthesis by heating urea with glycocoll 
at 200 C. (392 ° F.). When decomposed, urea is one of the 
products. Although uric acid does not contain the acid group 
CO OH, it has 3 groups of HNCO, which give it combining 
power toward bases and blood-serum. 



PURINS AND URIC ACID 489 

Properties. — Almost insoluble in water, uric acid is wholly in- 
soluble in alcohol and ether, but soluble in warm glycerin. Its 
solubility is much reduced when some other acid is present in sol- 
ution. It is a weak acid with 2 atoms of replaceable hydrogen, 
forming 2 classes of salts, like the acid sodium salt, NaC 5 H 3 N 4 3 , 
and the normal sodium salt, Na 2 C 5 H 2 N 4 3 . The normal salts 
are soluble, but the acid salts are soluble to a slight degree only; 
both are kept in solution in urine by the disodium phosphate. 
Two salts with organic bases are much more soluble — piperazin 
urate and lysidin urate; hence the use of these bases to dissolve uric- 
acid gravel. 

Murexid Test. — In a porcelain dish place some uric acid or a 
urate. Moisten with nitric acid and evaporate at a gentle heat. If 
no ammonia be present, a yellow stain of alloxantin is left. 

2C 5 H 4 N 4 3 + 2H 2 + 2 = 2C 4 H 2 N 2 4 + 2CON 2 H 4 

Uric acid. Alloxan. Urea. 

Continued heat splits alloxan into alloxantin, parabanic acid, 
and carbon dioxid: 

3 C 4 H 2 N 2 4 = C 8 H 4 N 4 7 + C 3 H 2 N 2 O s + C0 2 . 

Alloxan. Alloxantin. Parabanic acid. 

The yellow residue yields a red-purple color with ammonia, due 
to ammonium purpurate or murexid: 

C 8 H 4 N 4 7 + 2NH3 = C 8 H 8 N 6 6 + H 2 0. 

Alloxantin. Murexid. 

As xanthin and guanin both yield the red color, add 1 drop of 
sodium hydroxid and the uric-acid red turns blue. Moisten with 
water and evaporate to dryness; the color disappears. 

Experiment 1. — To a mixture of 50 c.c. of urine and 2.5 c.c. of 
concentrated solution of sodium carbonate add 5 c.c. of a saturated 
ammonium chlorid solution. On standing, ammonium urate is 
precipitated. 

Experiment 2. — If a small quantity of uric acid be shaken with 
water, it does not dissolve. Adding dilute potassium hydroxid, the 
soluble dipotassium urate is formed. Dilute acid will precipitate 
uric acid again. 

Purin Bodies. — Uric acid is the most highly oxidized member 
of a series of compounds considered to be derivatives of a syn- 
thesized substance, C 5 N 4 H 4 , called purin. The other members of 
the series, being basic, are called alloxuric bases or xanthin bases, 
after the second member given below. The nucleins found in cell 
nuclei decompose by acids and enzyms in such a way as to justify 



490 CYCLIC COMPOUNDS 

the view that they consist of protein combined with nucleic acid. 
The nucleic-acid molecule contains some of the purin and pyrim- 
idin bases united with orthophosphoric acid. As purin bodies 
are products of the decomposition of nucleins, they may be termed 
nuclein bases. They are considered to be intermediate stages of 
oxidation of nucleoproteins on the way to form uric acid. 

Uric acid, C 5 H 4 N 4 3 Heteroxanthin, C 5 H 3 (CH 3 )N 4 2 . 

Xanthin, C 5 H 4 N 4 2 Paraxanthin, C 5 H 2 (CH 3 ) 2 N 4 2 . 

Hypoxanthin, C 5 H 4 N 4 ...... Theobromin, C 5 H 2 (CH 3 ) 2 N 4 2 . 

, Theophyllin, C 5 H 2 (CH 3 ) 2 N 4 3 ; 
Guanin, QH,N,0 . . . . \ 

. l Caffein, C 5 H(CH 3 ) 3 N 4 2 . 

Adenin, C 5 H 5 N 5 Epiguanin, C 5 H 4 (CH 3 )N 5 0. 

It will be seen that in the second column are the methyl 
derivatives of the bodies in the first column. 

The purin bodies occur together, being found in the same sit- 
uation and in small amount in the urine, the blood, and many of 
the tissues. In rare cases the xanthin of the urine separates in the 
bladder and forms the xanthin calculus. They are found in all 
meat extracts, to which they impart a stimulating quality, but no 
food value. Some meat extracts contain, in addition, proteins, 
which are nutritive. 

The structure of these bases and their close kinship to uric acid 
will be better understood if the following graphic formulas are 
studied. The first two are purely hypothetic bodies: 

N=CH 
N-C | | 

| | HC C— NH 

C C Nv 

I > 



? CK 



N— C N^ N— C— N 

Alloxan nucleus. Urea nucleus. Purin. 

Uric acid and the xanthin bases may be considered as substi- 
tution products of purin by the radical hydroxyl, amido-, imido-, 
or methyl groups. The position of the substituted radicals is 
indicated according to the numbers in the diagram of the purin 
nucleus given below. The purin nucleus is made up by joining the 
carbon-nitrogen nuclei of urea and alloxan given above. 

1 N— C 6 

I I 
2C &C— N* 

3N—C— N o/ 

4 
Purin nucleus. 



PURINS AND URIC ACID 



491 



Hypoxanthin is 6 oxypurin 

HN— CO 

I I 
HC C— NH 



Xanthin is 2.6 dioxypurin: 
HN— CO 



I 
CO 



L 



NH 



N— C— N 
Guanin is 2 amino-, 6 oxypurin: 
HN— CO 

H 2 N.C C— NH 

II II > 

N— C— N 
Uric acid is 2.6.8 trioxypurin: 



HN— CO 

I I 
CO C— NH 

\co 

j-c— tto 



>CH 



HN— C— N 
Adenin is 6 aminopurin: 

N-C.NH. 

I I 
HC C— N 

)CH 

-C— NH 



Theobromin is 
xanthin: 



3.7 dimethyl - 



HN— CO 

I I 
COC— N.CH 3 

)CH 

-N 



Theobromin, 3.7 dimethylxanthin, C 5 H 2 (CH 3 ) 2 N 4 2 , occurs in 
the seed of Theobroma cacao, from which chocolate is made. 
Theophyllin occurs in tea used as a beverage, and it may be pre- 
pared synthetically from'dimethyluric acid. 

Caffein (tliein, guaranin), 1.3.7 trimethylxanthin, C 5 H(CH 3 ) 3 - 
N 4 2 , is found in tea, coffee, guarana, and other stimulating 
plants. It may be formed from trimethyluric acid. It is soluble 
in 80 parts of water, 35 of alcohol. 

Caffein citrate contains 50 per cent, of caffein. It is a white 
powder with an acid taste, soluble in 25 parts of water. Dose: 2 to 
10 gr. (0.13-0.65 gm.). 

Murexid Test. — To 0.5 gm. of caffein in a porcelain dish add a 
few cubic centimeters of strong fuming nitric acid and evaporate to 
dryness. A yellow stain is left, which on moistening with am- 
monium hydroxid becomes purple. 

Pyrimidin Bases. — When the nucleic acids break up, the prod- 
ucts are the purins referred to above and the bases uracil, thymin, 
and cytosin, which are derivatives of pyrimidin, C 4 H 4 N 2 . Pyrim- 
idin is obtained by splitting off one side of purin. Uric acid can 
be formed synthetically from these derivatives. The relationship 
is expressed in the following formulas: 
(3) N— C (6) HN— CO 



(2)C C( 5 ) 
(1) X=C (4) 

Pyrimidin nucleus. 



HN- 

oc 

I II 

N— CH 

Uracil. 



CH 



HN— CO 

I I 
OC C— NH 

I ii 

HN— C— NH 

Uric acid. 



\ 



CO 



492 CYCLIC COMPOUNDS 

Uracil, C 4 H 4 N 2 2 , has been found in the nucleoproteins, and so 
has thymin, C 4 H 3 N 2 2 . CH 3 , which is methyluracil. Cytosin, 
C 4 H 5 N 3 0, is a constant cleavage product of the nucleic acids. It is 
so intimately related to the purin group that it is supposed to be the 
mother-substance. 

Uric acid in the urine is derived from two sources — the internal 
and the external, or endogenous and exogenous. The endogenous 
uric acid comes from the nucleins of the body cells and their 
decomposition products, the purin bases. The quantity for each 
individual is fairly constant and uninfluenced by food. The 
exogenous uric acid arises from the nucleins and purin bases con- 
tained in the food. It is, therefore, an addition to the normal quan- 
tity and is dependent entirely on the amount of combined and free 
oxypurins and aminopurins in the food. These are abundant in 
sweetbreads (thymus gland), liver, kidney, meat soups, peas, beans, 
asparagus, heavy wines, meats, and fish. A purin-free diet may be 
made of bread, butter, milk, sugar, eggs, potatoes, rice, and green 
vegetables. When the diet is regulated so that there are no purins 
in the food, the output of uric acid is materially lessened. Theo- 
bromin, caffein, and other methylpurins in food have no effect 
on the uric-acid elimination, though they increase the amount of 
purin bases, such as xanthin and hypoxanthin, in the urine. In 
the process of metabolism of cell nuclei in the liver, kidney, and 
other organs, uric acid is a stage between the purin bases and a 
lower oxidation product. This end-product may be urea or 
allantoin or glycocoll or C0 2 and H 2 0. 

Nuclein 

I 
protein nucleic acid 

purin and pyrimidin bases phosphoric acid. 

Purin bases are partly oxidized by the liver to 

uric acid, which is again partly oxidized to 

urea of urine. 

Some of the purin bases, such as adenin, under certain con- 
ditions of the body have a marked toxic action. They are sup- 
posed to be factors in the production of febrile temperatures. 
Other nitrogenous waste substances, such as leukomains, creatin, 
etc., resulting from metabolism of cell protoplasm, have their 
formation augmented by a diet rich in proteins. 

In the urine the ratio of purin bases to uric acid is about i : 10. 
Expressed in terms of the nitrogen content, uric acid N is to that 
of the purin bases as 4 : 1. The total amount excreted daily varies 
between 0.0286 and 0.0561 gm. 



PURINS AND URIC ACID 



493 



Hall's Purinometer. — For clinical purposes it is sometimes 
desirable to determine the total sum of purin nitrogen in the urine, 
including that of uric acid. A simple and easy method is that of 
Walker Hall. His purinometer estimates by volume the amount of 
silver purins precipitated by ammoniosilver nitrate. 

Two solutions are required for solution No. i : Mix ioo c.c. of 
Ludwig's magnesia mixture, 1 ioo c.c. of ammonia (20 per cent.), 
and 5 gm. of finely powdered talc. 

Solution No. 2 is a mixture of silver nitrate, 1 gm.; strong 
ammonia, 100 c.c; finely powdered talc, 5 gm. ; and 100 c.c. of 
water. No. 1 precipitates the phosphates; No. 2 precipitates the 
purins, the silver chlorid being kept in solu- 
tion by the ammonia. The object of the talc 
is to make the precipitate heavy and definite. 

Directions. — Having measured and mixed 
the total urine of the day, 100 c.c. is made 
free of albumin (if present) by slightly acid- 
ulating, boiling, and filtering. With the stop- 
cock at right angles, 90 c.c. of urine and 20 
c.c. of solution No. 1 are poured into the 
graduated tube (Fig. 82) and the instrument 
inverted several times. The phosphates are 
precipitated and the stopcock is opened ver- 
tically. In ten minutes the phosphates settle 
into the lower chamber of the tube and the 
cock is again turned off at right angles, and 
No. 2 solution added up to 100 c.c. By free 
inversion of the tube several times the pale- 
yellow silver purin is freed of the white silver 
chlorid. If this does not occur, a few drops 
of strong ammonia may be added. The in- 
strument is placed in a dark cupboard for twenty-four hours, 
when the number of cubic centimeters occupied by the precip- 
itate is read off. 

A table is furnished with each instrument, which shows the 
nitrogen percentage yielded by each cubic centimeter of precipitate. 
This factor, multiplied by the total cubic centimeter of urine divided 
by 100, gives the total purin-nitrogen. 

Example: The silver purin precipitate amounted to 9 c.c. 
The table stated that 9 c.c. = 0.0175 per cent, purin-nitrogen. 
The total daily urine was 1 2 10 c.c. Then, 0.0175 X 12. 1 = 0-21175 
purin-nitrogen. 

Creatin, C 4 H 9 N 3 2 . — Associated with the purin bases in the 

1 Ludivig's magnesia mixture is composed of magnesium chlorid, no gm.; 
ammonium chlorid, no gm.; ammonia, 250 gm.; water, to 1 L. Mix. 




Fig. 82. — Purinometer. 



494 CYCLIC COMPOUNDS 

nitrogenous extractive of muscular tissue is creatin or methyl- 

NH 

guanidin acetic acid. It is a derivative of guanidin, NH . C<attt 2 > 

which is an oxidation product of guanin. The structural formula 
of creatin is that of a complex amino-acid. 

i\n . <^ N(CH3) CH2 m COOH. 

It is easily obtained as a product of metabolism from beef heart or 
the flesh of fowl by extraction with warm water. As a by-product 
in making "beef extract" it crystallizes with the residue of meat 
juice. Boiled with baryta water or other alkali, it breaks up into 
urea and sarkosin. By prolonged boiling with dilute hydro- 
chloric acid it loses a molecule of water and becomes the anhydrid 
creatinin, C 4 H 7 N 3 0, an ingredient of the juice of flesh, also of the 
blood and the urine. By its reducing action on alkaline copper 
solution when boiled it is the source of a fallacy in testing for 
glucose in the urine. Creatinin is a strong base forming a crys- 
talline double chlorid with zinc chlorid in alcoholic solution. 

Allantom, HN< CQ CH HN CQ NIV occurs in the 

allantoic fluid of cows, the urine of calves, dogs, and cats, newborn 
children, and pregnant women/ It is a product of enzym action 
on uric acid in liver, spleen, and pancreas. Crystalline and 
sparingly soluble in water, if heated with alkalis it breaks up to 
NH 3 . C0 2 , oxalic and acetic acids. 



AMMONIA DERIVATIVES 

AMIDS, AMINS, AMINO-ACIDS, AND ALKALOIDS 

Ammonia, NH 3 , plays a part in organic compounds by the sub- 
stitution of i or more univalent hydrocarbon radicals for an atom 
of its hydrogen. When the radical is basic, — that is, such as are 
found in the alcohols, — the product is called an amin; when the 
radical is acid, the compound is called an amid. 

Amids are neutral in reaction. They are produced when 
amidogen, NH 2 , replaces hydroxyl, HO, in a carbon acid. This 
is the result of a reaction between the HO of the COOH group 
and NH 3 . Thus: 



CH 3 .CO!OH + H;NH 2 = CH 3 . CONH 2 + H 2 0. 

Acetic acid. Acetamid. 



AAIIDS 495 

When ammonium acetate, NH 4 C 2 H 3 2 , is heated, H 2 escapes 
and acetamid, XH 2 C 2 H 3 0, remains as soluble crystals with a 
mousy odor. Other atoms of hydrogen may be displaced by re- 
action with NH 3 , and diacetamid produced. In a double molecule, 
2XH3 or X 2 H 6 , the radical carbonyl may be substituted for 2 
hydrogen acids, thus making carbamid or urea: 

/H /C 2 H 3 /C 2 H 3 /yQO 

N^H Nf H N^C 2 H 3 N 2 |=H 2 

Acetamid. Diacetamid. Carbamid. 

Amid and Stable Nitrogens. — When an amid is boiled with 
a caustic alkali, the stronger base displaces the weaker NH 2 from 
its union with the acid radical. Thus: 

CO(NH 2 ) 2 + 2 NaHO = Na,C0 3 + 2NH3. 

Lrea. Sodium carbonate. 

But the alkali has no affinity with the basic radical in the amins 
and amido-acids, and hence their nitrogen is not displaced by this 
means. It is stable and requires the action of strong sulphuric 
acid and potassium sulphate to form ammonium sulphate, as in 
KjeldahFs method (p. 365). 

Nitrous acid (HN0 2 ) has the power of substituting OH for 
and breaking up all NH 2 groups, whether amid, amin, or amido- 
acids. Thus, if a mixture of ethylamin hydrochlorid, C 2 H 5 XH 2 = 
HC1, and potassium nitrite be added to glacial acetic acid, the 
nascent nitrous acid causes 2 atoms of nitrogen to be evolved and 
ethyl alcohol, C 2 H 5 . HO, is left. Sodium hypobromite, XaOBr, 
in alkaline solution splits off N from NH 2 groups, but only to 
the extent of 90 per cent. ; hence the calculation of nitrogen contents 
by this method is not so accurate as by that of Kjeldahl (p. 365). 

Urea (carbonyl diamid, carbamid) is present in the urine of 
mammals and of carnivorous birds and reptiles; also in the blood, 
the muscles, and various animal fluids. Its constitution has been 
made out by the synthetic reactions given on pp. 193 and 200. It is 
the chief solid constituent of human urine, and is generated mainly 
in the liver, from nitrogenous waste substances. The nitrogen of 
the urea parts from the muscular tissue as ammonium lactate. 
The lactate easily changes in the tissues to carbonate. The ammo- 
nium carbonate is dehydrated by the liver cells, forming first am- 
monium carbamate and lastly urea: 

co <8S5; iess H °° - co <SSk, iess H >° - co <nS: 

Ammonium carbonate. Ammonium carbamate. Urea. 

It occurs in white or colorless needles with a cool and bitter taste. 
It melts at 132 ° C. (270 F.) and readily dissolves in water and 



496 CYCLIC COMPOUNDS 

alcohol. When heated to 120 C. (248 ° F.) in the presence of 
water it forms ammonium carbonate: 

CO . N 2 H 4 + 2 H 2 = (NH 4 ) 2 C0 3 . 

When heated without water, it breaks up into cyanuric acid and 
ammonia: 

3 CON 2 H 4 = H3N3O3 + 3NH3. 

Cyanuric acid. 

Fuming nitric acid decomposes it into nitrogen and carbon 
dioxid: 

CO.N 2 H 4 + 2 HN0 2 = C0 2 + N 2 + 2 H 2 0. 

Hypochlorites and hypobromites have a similar effect, giving off 
C0 2 and N: 

CO . N 2 H 4 + 3NaOBr = C0 2 + N 2 + 2 H 2 + 3 NaBr. 

If the C0 2 be fixed by passing through alkaline solution, then 
the free nitrogen may be measured and an estimate made of the 
quantity of urea required to produce that amount (p. 592). 

The solution of urea is neutral in reaction, though its relation 
to acids is basic. It combines with one equivalent of acids to 
form salts, the most characteristic of which is urea nitrate, CO- 
(NH 2 ) 2 , HNO3, crystallizing in glistening plates. It unites with 
metals to form such compounds as HgO . CO(NH 2 ) 2 and HgCl 2 - 
CO(NH 2 ) 2 . 

Tests. — Nitrate. — Evaporate fresh urine on a water-bath to a 
syrupy consistence. On cooling, add strong nitric acid, and crys- 
tals of urea nitrate will appear. Having separated the crystals 
by nitration, they are dissolved in boiling water and the solution 
treated with barium carbonate. This forms barium nitrate and 
free urea in the solution, which is then evaporated to dryness and 
the residue treated with hot alcohol, thus extracting the urea and 
leaving the barium nitrate. Filtration gives a clear solution which, 
on evaporation, deposits crystals of urea. 

Biuret. — The urea formed above is carefully heated in a test- 
tube to about 160 C. (320 F.) until no more ammonia comes 
off. It is then allowed to cool. The residue is a substance called 
biuret, which, if treated with a few drops of potassium hydroxid and 
of copper sulphate, will yield a violet-red color (Plate 8, Fig. 7): 



CO( 



/NH 2 
-=NH 8 + )NH 

co< 

X NH 2 



CO 

Urea. Biuret. 



amins 497 

Two molecules of urea combine, excluding NH 3 to form biuret. 

Urea has diuretic properties esteemed of value in the treatment 
of dropsies. Dose: 10 to 20 gr. every hour in water. It is incom- 
patible with chloral hydrate and lead acetate. 

Formamid, N(CHO)H 2 , is a colorless liquid made by heating 
an alcoholic solution of ammonia with ethyl formate. It unites 
with chloral, forming chloralamid, N(CH0)H 2 C 2 HC1 3 0, a recently 
introduced hypnotic. It occurs in colorless, bitter crystals, sol- 
uble in water and alcohol, and decomposable by hot solvents. 
Dose: 15 to 45 gr. It is incompatible with silver nitrate and the 
alkalis. 

Amins are said to be primary, secondary, or tertiary, according 
to the number of atoms of hydrogen in NH 3 which have been re- 
placed by the basic radical. The production is illustrated in the 
three classes of amins of ethyl, C 2 H 5 , from ethyl bromid, C 2 H 5 Br, 
by the following series of equations: 

C 2 H 5 Br + NH 3 = NH 2 . C 2 H 5 . HBr— >NH, . C 2 H 5 , Ethvlamin; 

C 2 H 5 Br + NH 2 . C 2 H 5 = NH(C 2 H 6 ) 2 HBr — >NH(C 2 H 5 ) 2) Diethvlamin; 
C 2 H 5 Br -f NH(C 2 H 5 ) 2 = N(C 2 H 5 ) 3 . HBr — ^N(C 2 H 5 ) 3 = Triethylamin. 

The salts in the middle column treated with KOH form KBr-f- 
H 2 and the amins of the last column. 

The following formulas represent the constitution on the am- 
monia plan: 



N=sNErNE! s 'NElN3! 

Ammonia. Ethylamin. Diethylamin. Triethylamin. 



MethyK 
Ethyl Aamin. 
Butyl / 



They are a very important class of basic substances, soluble 
in water, alkaline in reaction, and have a strong odor similar to 
ammonia. Like ammonia, also, they precipitate metallic salts 
and react with acids to form salts without elimination of water. 

NH 3 + HC1 = NH 4 C1. % 

N(C 2 H 5 ) 3 + HC1 = N(C 2 H 5 ) 3 HC1 

Triethylamin. Triethylamin chlorid. 

An amin is the result of a reaction between the OH group of 
an alcohol and NH 3 . Thus: 



C 2 H 5 ;OH + H;NH 2 - C 2 H 5 . NH 2 + H 2 0. 

Ethyl alcohol. Ammonia. Ethylamin. 

Another view of the constitution of the amins is to consider 
them as hydrocarbons with the hydrogen replaced by nitrogen 
32 



498 CYCLIC COMPOUNDS 

radicals. The primary amins having the amino group NH 2 in 
them are called amino-compoiinds; thus, methylamin, NH 2 CH 3 , is 
amino-methyl. The secondary amins are called imins or imino- 
compounds, from the' imino group, NH; thus, dimethylamin, 
NH(CH 3 ) 2 , is imino-dimethyl. 

Carbylamin or Isonitril Reaction. — When warmed with 
chloroform and alcoholic potash, ethylamin and all primary amins 
quickly undergo a change to carbylamins or isonitrils which have 
an unbearable, characteristic odor: 

C 2 H 5 . NH 2 + CHCI3 + 3KOH = C 2 H 5 NC + 3KCI + 3H 2 0. 

Ethylamin. Carbylamin. 

Trimethylamin is an isomer of propylamin, N(CH 3 ) 3 . It is 
found in fish brine, and is a product of putrefactive decomposi- 
tion in brain tissue, muscle tissue, and starch paste. In the form of 
a 10 per cent, solution it is used in the treatment of rheumatism. 
It is a colorless liquid with a strong, fishy, and ammoniacal odor. 
Dose: 15 to 45 min. 

Urotropin (formin) is a condensation product when ammonia 
reacts with formaldehyd, 6CH 2 + 4NH 3 = (CH 2 ) 6 N 4 + 6H 2 0. 
The odor of formaldehyd disappears in the process. It is hexa- 
methylenamin, (CH 2 ) 6 N 4 , U. S. P. It occurs in soluble crystals, 
used as a diuretic and solvent for uric-acid concretions. It is 
said to act as an antiseptic by liberating formaldehyd in the urinary 
passages. Dose: 7 J to 15 gr. (J-i gm.). 

Amino=acids are regarded as being produced by substituting 
the amino group, NH 2 , for HO in the alcohol group of an oxyacid. 

COOH. CHJOH "+ H:NH 2 = COOH. CH 2 NH 2 + H 2 0. 

Oxyacetic acid. Amino-acetic acid. 

In reaction they are amphoteric. Since the acid and the base are 
not in direct union, but joined to different carbon atoms, each group 
retains its own reaction. They are basic because they have the 
NH 2 , and are acid at the same time because of the COOH group. 
When chemically inactive these neutralize each other, but in the 
presence of ions they form anions and kations, according to 
the nature of the exciting ion. They are more stable than the 
amids and number certain important physiologic compounds. The 
protein molecule is composed almost entirely of them, the acid group 
of one linked to the amino- (basic) group of the next like a train 
of cars. Their constitution and relation to amids are shown below: 

CH 3 CH 3 CH 2 OH CH 2 (NH 2 ) 

III I 

COOH CO(NH 2 ) COOH COOH 

Acetic acid. Acetamid. Oxyacetic acid. Amino-acetic acid. 



AMINO-ACIDS 



499 



As the NH 2 may be joined to any C atom in a chain and with 
each variation of position make a different compound, the amino- 
acids are named according to the position in relation to the CO OH 
group, alpha-, beta-, gawwa-aminobutyric or other acid (p. 422). 

Glycin (CH 2 (NH 2 ) . CO OH) {glycocoll, amino-acetic acid) 
occurs in animal secretions, usually in combination like uric acid. 
As benzoyl- glycin or hippuric acid, C 6 H 5 . CO . NH . CH 2 . CO OH, 
it occurs in considerable amounts in the urine of herbivora; and 
to the extent of about 2 gm. daily in human urine. This amount 
is much increased when benzoic acid and other aromatic sub- 
stances are taken; Some of the urea made in the liver may be an 
oxidation product of glycocoll reacting with NH 3 . Thus: 



CH 2 .NH 2 .COOH + NH 3 + O 

Glycocoll. 



CO(NH 2 ) 2 + C0 2 + H 2 0. 

Urea. 



OH 




Glycin can be prepared as hydrochlorid from hippuric or gly- 
cocholic acid by treatment with HC1 (p. 465). It contains an 
amino-group and a carboxyl group, and, therefore, has 
both acid and basic properties, uniting on the one 
hand with HC1 to make glycin hydrochlorid or, on 
the other, with NaHO to form sodium glycocollate 
and water. It is relatively abundant as a nucleus 
in the proteins. It crystallizes in colorless prisms, 
soluble in water, giving a red color with ferric chlorid, 
and with phenol and sodium hypochlorite an intense 
blue. 

Other amino-acids of physiologic importance are 
aminopropionic acid (alanin), aminocaproic acid (leucins), amino- 
glutaric acid (glutamic), aminosuccinic acid (aspartic), diamino- 
caproic acid (lysin), diaminovaleric acid (ornithin). 



CH« 



CHNH 2 

i 

COOH 

Ty rosin. 



COOH 

I 
CHNH 2 

I 
CH 3 

Alanin. 



COOH 
CHNH 2 
(CH 2 ) 3 
CH 3 

Leucin. 



COOH 

I 
CHNH 2 

(CH 2 ) 3 

I 
CH 2 NH 2 

Lysin. 



COOH 

I 
CHNH 2 

(CH 2 ) 2 



CH 2 NH 2 

Ornithin. 



Alanin is present free in proteins and also in combination with 
phenol to form tyrosiri, and with indol to form tryptophan. 

Leucin is very abundant in all proteins, and is one of the end- 
products of their digestion. Having an asymmetric carbon atom, 
it has not only the ordinary isomers, but those that are either 
dextro- or levorotatory. 



500 CYCLIC COMPOUNDS 

Ornithin is the precursor of uric acid in its synthesis in birds. 
It is present in proteins combined with guanidin to form arginin. 

Lysin is a product of the tryptic digestion of fibrin. When the 
protein molecule is attacked by the bacteria of putrefaction, C0 2 
is split off from ornithin to form putrescin; from lysin to form 
cadaverin. The acid character is lost with the C0 2 . 

CH 2 NH 2 . (CH 2 ) 2 . CHNH 2 . COOH = CH 2 NH 2 . (CH 2 ) 2 . CH 2 NH 2 -f C0 2 

Ornithin. Putrescin. 

CH 2 NH 2 (CH 2 ) 3 . CHNH 2 . COOH = CH 2 NH 2 .(CH 2 ) 3 . CH 2 NH 2 -f C0 2 

Lysin. Cadaverin. 

In this way other ptomains are formed from other amino-acids 
by putrefaction. 

Tyrosin (1:4 phenolamino propionic acid), is a constituent of 
the protein molecule and is produced by many of its decom- 
positions. It has also been prepared synthetically. Having the 
HO phenol group, it gives Millon's reaction. While tyrosin is 
phenol + alanin, it may condense to indol, and indol + alanin 
become tryptophan. It may therefore be regarded as a binary 
compound, like tryptophan. 

Tryptophan {skatol amino-acetic acid) exists in the protein 
molecule and is liberated by tryptic di- 
CH 2 NH 2 gestion. It is the cause of the Adam- 

iCH COOH kiewicz reaction given by proteins (a vio- 
let color when treated with sulphuric and 
acetic acids). It is regarded as the 
NH mother-substance of indol, skatol, and 

Tryptophan. skatolcarbonic acid, which are formed 

from the proteins by the bacteria of 
putrefaction. In the graphic formula appended its constitution is 
represented as skatol linked to amino-acetic acid. 

Glucosamin, CHO . CHNH 2 . (CHOH) 3 CH 2 OH, is an amin 
in combination with sugar, existing as a component of the 
protein molecule. Polymeric forms of an insoluble character 
are called chitosamins, and these mixed with calcium salts make 
the shells of crustaceae. Molisch's reaction (p. 473), given by 
albuminous substances, denotes glucose in the molecule. The 
large quantities of sugar excreted in diabetes, even when there is 
no carbohydrate in the food or stored in the liver, is due to the 
splitting of the glucose nucleus from pure proteids by hydrolysis. 

C 6 H n 5 NH 2 + H 2 = C 6 H 12 6 + NH 3 . 

Serin and Cystin. — Amino-acids may be derived from oxyacids 
by substitution of NH 2 in a hydrocarbon group or for alcoholic 




ALKALOIDS 501 

HO in acids containing more than one such group. Serin is 
a-amino-,5-oxypropionic acid (CH 2 OH . CHNH 2 . CO OH), a cleav- 
age product of silk fiber which is a simple form of protein. 
Closely related to serin is cystin, the compound which holds most 
of the sulphur of the protein molecule. It contains two molecules 
of cystein, which is the acid corresponding to serin: 

CH 2 SH.CHNH 2 . COOH 

Cystein. 

HOOC . CHNH 2 . CH 2 S . SCH 2 . CHNH 2 . COOH 

Cystin. 

Cystin or a-diamino-/?-dithiodilactic acid is formed by hydrolysis 
of proteins, especially the keratins of hair, horns, and hoof. When 
produced in the body by metabolism and not decomposed, it is 
found in the urinary sediment, which may accrete to form the 
cystin calculus (p. 622). By feeding animals with cystin the 
amount is increased of taurin, CH 2 OH . CH 2 S0 3 H 2 , a constit- 
uent of the bile acids (p. 558). The easy production of taurin 
from cystin artificially points to the origin of the bile constituents 
from the cystin of the protein molecule. 

ALKALOIDS 

Alkaloids are nitrogenous principles of alkaline reaction and 
basic properties. They are found in plants, and in most cases 
have important physiologic effects. A few alkaloids, such as 
coniin, nicotin, spartein, are volatile liquids, composed of carbon, 
hydrogen, and nitrogen only. More than a hundred contain oxy- 
gen in addition to carbon, hydrogen, and nitrogen; have a high 
molecular weight, and are solid, crystalline, and non-volatile. 

Generally speaking, the alkaloids, the constitution of which 
has been established, are tertiary aromatic bases, heterocyclic, 
containing at least one ring having a nitrogen atom in the nucleus. 
Exceptions to this are theobromin and caffein, which are purin 
bases (p. 491). 

Many of these alkaloids are known to be derivatives of pyrroli- 
din, pyridin, piperidin, quinolin, or isoquinolin, and contain the 
pyridin ring. It is customary to regard them as secondary and 
tertiary amins, because they have many reactions like ammonia, 
combining directly with acids to form crystalline salts without 
elimination of hydrogen or water. Thus: 

2NH3 + H 2 S0 4 = (NH 3 ) 2 H 2 S0 4 or (NH 4 ) 2 S0 4 . 
2(C 17 H 19 3 N) + H 2 S0 4 = (C 17 H 19 3 N) 2 H 2 S0 4 

Morphin. Morphin sulphate. 



502 



CYCLIC COMPOUNDS 



General properties of the alkaloids are as follows: 
The liquid alkaloids are volatile, having a disagreeable odor, 
somewhat ammoniacal; the solid alkaloids are without odor. Gen- 
erally speaking, the solid alkaloids melt without decomposition 
when heated carefully above ioo° C. (212 ° F.). A much higher 
temperature decomposes them. Most of them are white, crys- 
talline, and bitter; and as free bases are sparingly soluble in 
water, but dissolve readily in alcohol, chloroform, ether, petro- 
leum ether, benzene, and amyl alcohol. On the other hand, their 
salts (chlorids, sulphates, nitrates, acetates, etc.) are mostly sol- 
uble in water or acidulated water, and in alcohol; but, with few 
exceptions, are insoluble in chloroform, ether, petroleum ether, 
benzene, and amyl alcohol. 

In their physiologic action, as a rule, they display great energy: 
witness the convulsive effects of strychnin, the coma induced by 
morphin, the cardiac depression caused by veratrin and aconitin. 
They are alkaline, unite directly with acids to form soluble salts, 
and are liberated from this union by the action of alkaline 
hydroxids and alkaline carbonates, which precipitate them from 
solution. They are also precipitated by lime, baryta, and mag- 
nesia. Other general reagents for precipitating alkaloids, used for 
their detection and isolation, are phospho- 
molybdic acid, potassium mercuric iodid, picric 
acid, tannic acid, and platinum chlorid. Dilute 
tannic acid and substances containing it, such 
as strong tea and the vegetable astringents, are 
used to wash out the stomach as precipitants in 
alkaloidal poisoning. 

Characteristic color changes are produced in 
most alkaloids by oxidizing agents, such as 
nitric acid, ferric chlorid, potassium dichro- 
mate, and sulphuric acid. 

Extraction of Alkaloids.— The bark, seeds, 
leaves, or roots of plants are ground up and 
macerated with dilute acids, which dissolve 
out the alkaloids as corresponding salts. This 
solution, after filtration, is treated with soda 
to liberate the alkaloid bases. If volatile, the 
free alkaloids may be distilled off; if non- 
volatile, the free alkaloids are usually nearly 
insoluble, and hence are precipitated, to be separated by filtration. 
To purify them they must be redissolved in acids, again pre- 
cipitated with alkali, and recrystallized. 

If this method does not promise satisfactory results, the alka- 
line aqueous extract is shaken out with chloroform, ether, or other 




Fig. 83. — Separating funnel. 



ALKALOIDS 503 

solvent not miscible with water. The solvent is then put in a 
separating funnel and allowed to form two layers, which are 
separated by permitting the heavier to flow through the open 
stopcock into an evaporating dish (Fig. 83). The volatile liquid 
— chloroform, ether, etc. — used as a solvent is evaporated and the 
alkaloid is left in the dish. 

Antidotes to Alkaloids in General.— The stomach should be 
washed out through a siphon tube, using freely water, strong 
tea, or solution of tannic acid, or solution of 10 gr. of potas- 
sium permanganate in 16 fl. oz. of water. If the tube be not 
practicable, vomiting should be induced by teaspoonful doses of 
mustard or 20-grain doses of zinc sulphate, or hypodermic injec- 
tions of apomorphin — 5 drops of a 2 per cent, solution. After 
evacuation of the stomach and administration of 10 grains potas- 
sium permanganate in a tumbler of water, the dangerous symp- 
toms are combated with remedies which are physiologic antago- 
nists — that is, stimulants, such as whisky and ammonia; artificial 
respiration, etc. 

Detection of Alkaloids in Animal Mixtures.— No oper- 
ation of the toxicologist demands so much expert skill as that of 
separating from organic matter an alkaloid in a state so pure as 
to justify the analyst in swearing to its identity. The technical 
problem is rendered more complex by the presence, in decaying 
animal substances, of cadaveric alkaloids or ptomains, behaving 
chemically, if not physiologically, like the vegetable alkaloids. 
(For the details of this procedure see p. 521'.). 

Classification of Important Alkaloids.— The constitu- 
tion of many alkaloids is as yet undetermined; some; of them, 
however, are known to be derivatives of or to contain the^nuclei 
of the heterocyclic compounds pyrrolidin, piperidin (p. 484), 
pyridin, quinolin, isoquinolin, and phenanthrene. According to 
these complex nuclei found in them, the commonly used alkaloids 
named below are classified as derivatives of — 

1. Pyrrolidin. — The poisonous hygrins of coca. 

2. Pyridin. — Pilocarpin of jaborandi. 

3. Piperide'in. — Arecolin of betelnut, pelletierin of jaborandi. 

4. Piperidin. — Coniin of hemlock, piperin of pepper. 

5. Pyrrolidin-pyridin. — Nicotin of tobacco. 

6. Pyrrolidin-piperidin. — The tropan alkaloids, such as atropin 

of nightshade, hyoscyamin of henbane cocain, and ecgonin 
of coca. 

7. Quinolin. — The cinchona alkaloids; also strychnin and 

brucin. 

8. Isoquinolin. — Narcotin, narcein, papaverin of opium, and 

hydrastin of yellow root. 



504 CYCLIC COMPOUNDS 

9. Phenanthrene. — Morphin and codein of opium. 
10. Oj Unknown Constitution. — Veratrin, aconitin, ergotin, 
gelsemin, physostigmin, and many others. 

PYRIDIN ALKALOIDS 

Pilocarpin, C n H 16 N 2 2 , is an alkaloid found in jaborandi 
(pilocarpus). Its structure is not perfectly known, but its reactions 
are those of a compound containing the pyridin ring with the 
group C 6 H 12 N0 2 linked in the j3 position. Like atropin and 
cocain, it is an ester decomposed by alkalis. It is crystalline, 
colorless, soluble, and alkaline. The official salt is the hydro- 
chlorid. It is used as a diaphoretic and miotic. Dose: 0.1 to 
0.5 gr. (0.005-0.03 gm.) hypodermically. If instilled into the eye 
to contract the pupil, 1 or 2 drops of a 1 per cent, solution. 

Incompatibles: mercuric chlorid, silver nitrate, tannin, iodids, 
atropin. 

Toxicology. — The symptoms produced by pilocarpin in full 
doses are copious sweating, salivation, increase of milk and other 
secretions, contracted pupils, diminished blood-pressure, lower 
temperature, and prostration. 

Treatment. — After evacuation of the stomach and washing out 
with solutions of tannin, the physiologic antagonist is given — 
atropin, gV g r -> hypodermically. Whisky and ammonia are use- 
ful as stimulants. 

PIPERIDIN ALKALOIDS 

Coniin, C 8 H 17 N, is prepared from the seeds of the spotted 
hemlock by distillation with soda. At first it is a colorless oil, 
but later changes to brown. It has an acrid taste, a penetrating 
mousy odor, and is soluble in water. It is strongly basic, form- 
ing soluble salts. It is one of the simplest alkaloids in constitu- 
tion, and the first instance of one prepared synthetically. It is 
a-propylpiperidin, as is shown in these formulas: 



CH 



A 



CH 2 CH 2 

H 2 Cj/ \.CH 2 H 2 C|/ \cH 2 

H 2 cl JcH, H 2 c'\ JcHC 3 H y 



HCk ycH 

N NH NH 

Pyridin. Piperidin. Coniin. 

Toxicology. — Symptoms. — Coniin is exceedingly poisonous to 
the motor centers, a few drops sufficing to paralyze the muscles 
of respiration in from one to three hours. It produces great 
prostration, headache, weakness' or paralysis of the extremities, 



NICOTIN 505 

dilated pupils; the intellect remains clear until death occurs by 
failure of respiration. Two grains would probably prove fatal. 

Treatment. — The stomach should be washed out after giving 
tannic acid or vegetable astringents. The indications are for 
strong coffee, whisky, and strychnin hypodermically. Artificial 
respiration may be necessary. 

Tests. — (1) The odor is that of a mouse's nest. 

(2) Touched with alloxan, coniin develops a purple-red color 
and white crystals. The crystals, touched with potassium hy- 
droxid, evolve the odor of mice and turn purple. 

(3) Warmed with potassium dichromate and sulphuric acid, 
coniin yields butyric acid, detected by its odor. 

(4) Coniin placed on the tongue of a small animal causes un- 
steady gait, paralysis, convulsions, tremor, dilated pupils, and 
death in a few minutes. 

PYRROLIDIN-PYRIDIN ALKALOIDS 

Nicotin, C 10 H 14 N 2 , is prepared from the leaves of the tobacco 
plant by distilling the aqueous extract with milk of lime. Further 
steps are necessary to render it pure. 

It is a colorless oil, turning brown on exposure. It has a burning 
taste, a pungent, disagreeable odor, like that of an old pipe, and 
is soluble in water. It is a strong diacid base, forming salts 
which crystallize. By oxidation with chromic acid it yields 
nicotinic acid (pyridin-/9-carboxylic acid), C 5 H 4 N . CO OH, proving 
it to be a pyridin derivative with the pyridin nucleus: 

CH 

HCf |COOH 

Hcl JcH 

N 
Nicotinic acid. 

Toxicology. — Nicotin is fatally poisonous in doses of 2 or 3 
drops of the alkaloid, taken into the stomach. Four drops will 
kill a dog within five minutes. An infusion or decoction of tobacco 
leaves is the common form by which nicotin poisoning is induced. 
It may be swallowed or given by enema, intentionally or by mistake. 

The symptoms are nausea, vomiting, muscular relaxation, gid- 
diness, numbness, dilated pupils, diuresis, collapse with cold, 
damp skin, small and thready pulse, and death by heart failure. 
When the dose is very large, unconsciousness occurs immediately; 
and after a few respirations death follows within five minutes. 



506 CYCLIC COMPOUNDS 

Treatment. — If time permits and there has been no free vomiting, 
the stomach must be washed out with abundance of warm water 
or tea. The patient is kept recumbent and warm, while stimulation 
is practised with whisky or by hypodermic injections of strychnin 
nitrate, Jg. gr. 

Detection. — Its reactions are not very characteristic. With 
nitric acid it gives an orange color; with hydrochloric acid, a violet. 
Dissolved in ether and mixed with an ethereal solution of iodin, 
it yields an oily resin of brownish color, which in time forms crystals. 
Its presence may be detected by the familiar odor of stale tobacco. 

PYRROLIDIN-PIPERIDIN ALKALOIDS 

Atropin (C 17 H 23 N0 3 ) (Atropia, Atropina). — From the plants of 
the Solanacese — belladonna, stramonium, hyoscyamus, scopola, 
and duboisia — are obtained four important alkaloids — atropin or 
daturin, belladonin, hyoscyamin, and hyoscin or scopolamin. 

The deadly nightshade (Atropa belladonna) contains two alkaloids 
isomeric and much alike in properties: hyoscin and hyoscyamin. 
The latter, when treated with potash, changes to atropin by re- 
arrangement of its atoms. All of these and the coca alkaloid, 
cocain, also contain a methylated pyrrole ring (p. 483) in com- 
bination with a piperidin ring (p. 484). 

Properties. — Atropin forms glistening prismatic needles, odor- 
less, bitter, almost insoluble in water, but readily soluble in chloro- 
form, alcohol, and ether. It is strongly basic, neutralizing acids, 
forming salts, of which the sulphate is characterized by its ready 
solubility. Atropine sulphas, (C 17 H 33 N0 3 ) 2 H 2 S0 4 , is either crys- 
talline or amorphous, and is used in medicine instead of the base. 

When atropin or hyoscyamin is boiled in baryta water, it under- 
goes hydrolysis, breaking up into tropic acid and the base, tropin: 

C 17 H 23 N0 3 + H 2 = C 6 H 5 CH<^ 2 ( ^ + C 8 H 15 NO 

Atropin. Tropic acid. Tropin. 

This is a reversible reaction, as shown when, by synthetic 
methods, the components, tropic acid and tropin, are first built 
up and then readily combine to form atropin and water. 

Homatropin hydrobromid, C 16 H 21 N0 3 . HBr, is the isalt of an 
alkaloid obtained by the condensation of tropin and mandelic 
acid. It is a white, colorless, odorless, water-soluble powder, used 
as a rapid and transient mydriatic. It gives Vitali's test. 

Physiologic Effects. — Atropin is a depressant of the cerebro- 
spinal nervous system, but a stimulant to the sympathetic. It 
dilates the pupils, paralyzing ocular accommodation; increases the 



COCAIN 507 

blood-pressure and the force and frequency of cardiac action; 
deepens the respiration; flushes the face; diminishes the secre- 
tion of sweat, saliva, milk, and bronchial mucus. It is used as 
an antispasmodic, an anodyne, and an antidote to physostigma 
and opium. Dose: -j-J^ to J ff gr. 

A 1 per cent, solution is dropped into the eye to paralyze 
accommodation and dilate the pupil for eye-testing, and to treat 
iritis. 

Toxicology. — An overdose causes delirium, very rapid pulse, 
dry throat, thirst, flushed skin like a scarlatinal rash, pupils widely 
dilated, vision impaired, giddiness, muscular incoordination, 
retention of urine. In the later stage coma succeeds the noisy 
delirium, and the respiration becomes slow and shallow, death 
ending the scene with cardiac or respiratory paralysis. 

Treatment. — After washing out the stomach with a solution of 
tannic acid or evacuation by an emetic, hypodermic injection of 
strychnin is given to stimulate respiration; of morphin cautiously 
to allay the cerebral excitement of the first stage. In case of 
collapse heat is applied to the feet and epigastrium, and tea or 
whisky administered. 

Postmortem appearances are in no way characteristic. 

Tests. — VitaWs. — A trace of atropin or its salts, moistened 
with fuming nitric acid and dried on a water-bath, yields a yellow 
residue (that of morphin would be red), which, moistened with 
alcoholic potash, gives a violet solution, changing to red. 

A few drops of sulphuric acid dissolve a fragment of atropin 
without change of color; a crystal of potassium dichromate added 
will, after a while, turn the mixture green, and on warming with a 
little water develop an odor of orange blossoms. 

Physiologic. — Dropped into the eye of a cat, a solution of 
atropin dilates the pupil widely. 

Cocain (C 17 H 21 N0 4 ). — Of the several alkaloids of Erythroxylon 
coca this is the only one of importance in medicine. It is obtained 
in colorless prismatic crystals, which fuse at 98 C. (208. 4 F.) 
and are sparingly soluble in water. It is bitter and later benumb- 
ing to the sense of taste. Chemically, it resembles atropin, being 
strongly alkaline and forming salts, of which the hydrochlorid is 
used extensively in medicine. This is soluble in one-half part of 
water, and also in alcohol, glycerin, and chloroform. Heat should 
not be used in preparing its solutions. Boiled with water, it is 
hydrolyzed into benzoyl-ecgonin, and if acids or alkalis be present, 
further hydrolysis occurs, with formation of ecgonin, benzoic acid, 
and methyl alcohol: 

C 17 H 21 X0 4 + 2 H 2 = C 9 H 15 N0 3 + C 6 H 5 . COOH + CH 3 OH. 

Cocain. Ecgonin. Benzoic acid. 



508 CYCLIC COMPOUNDS 

This reaction shows that cocain is the methyl ester of benzoyl 
ecgonin. Locally to mucous membranes, or hypodermioally, 
cocain acts as an anesthetic, rendering minor surgical operations 
painless. It is given internally to relieve nausea. Dose: -i- to \ 
gr. (0.015-0.03 gm.). For local application a solution is used, 
2 to 10 per cent. 

Toxicology. — In overdoses cocain causes nausea, vomiting, 
vertigo, muscular prostration, and heart failure. Both pulse and 
breathing are much disordered. At times there is blindness, 
aphonia, or convulsions. 

The habitual use of cocain, or cocainism, causes deterioration 
of the moral sense and varied nervous phenomena. 

Treatment. — In treating cocain poisoning, after evacuation of 
the stomach the chemical antidotes are those used for all alka- 
loids: tannin and vegetable astringents; iodin, 1 gr., and potas- 
sium iodid, 10 gr., dissolved in water. The physiologic antago- 
nists are digitalis and inhalations of amyl nitrite for the syncope; 
caffein and whisky as stimulants; oxygen for cyanosis; morphin 
for nervous excitement. 

Detection. — (1) Iodin dissolved in potassium iodid solution 
precipitates cocain red. 

(2) Picric acid gives a yellow, powdery precipitate when the 
cocain is in concentrated solution. 

(3) The suspected solution is boiled for a few minutes with sul- 
phuric acid, neutralized with potassium hydroxid, and then treated 
with a few drops of ferric chlorid. Ferric benzoate is precipitated 
brownish yellow. 

Physiologic Test. — A neutral solution of the cocain hydrochlorid 
applied, several drops in succession, to tongue or lip causes numbness 
and insensibility, lasting a few minutes only. The same effect is 
obtained on the eye with some transient dilatation of the pupil. 

Eucain is an artificial alkaloid, employed locally as a substitute 
for cocain, because safer. There are two forms, alpha and beta. 
Alpha-eucain, C 19 H 27 N0 4 HC1, is a benzoyl-methyl-tetra-oxy-piperidin- 
carboxylic-methyl-ester. Beta-eucain, C 17 H 21 N0 2 HC1, is a benzoyl- 
vinyl-diaceton-alkamin. A white, neutral, water-soluble powder, less 
toxic on the heart than cocain or alpha-eucain, and sterilizable without 
decomposition by boiling. Used in 2 per cent, solution. 

QUINOLIN ALKALOIDS 

Quinin (C 2Q H 24 N 2 2 ).— This and several other allied alkaloids 
(cinchonin, quinidin, cinch onidiri) occur in cinchona bark, com- 
bined with quinic and quinotannic acids. The best varieties of 
calisaya contain 4 per cent, of ether-soluble alkaloids, of which 3 
per cent, is quinin. The crystalline form contains 3 molecules of 



CINCHONIN 509 

water and is with difficulty soluble in water. It is a feeble diacid 
base, forming hydrogen salts with sulphuric acid — the sulphate, 
(C 20 H 24 N 2 O 2 ) 2 H 2 SO 4 +7H 2 O, and the bisulphate, C 20 H 24 N 2 O 2 . - 
H 2 S0 4 + 7H 2 — both of which crystallize in silky needles, light, 
bitter, and soluble. The solutions are fluorescent, with a pale-blue 
color. The bisulphate is by far the more soluble. The sulphate 
contains 75 per cent, anhydrous quinin and requires 720 parts 
of water or 86 of alcohol to dissolve it; the bisulphate has 60 per 
cent, anhydrous quinin and requires for solution only 9 parts 
of water or 18 of alcohol; the salicylate has 70 per cent, anhydrous 
quinin and dissolves in 77 parts of water or 11 of alcohol. 

It has been established that quinin is a methoxycinchonin and 
a derivative of quinolin, because with oxidizing agents it yields 
quininic acid (methoxyquinolin-^-carboxylic acid). Both alkaloids 
contain a group, C 10 H 15 (OH)N, the structure of which is undeter- 
mined. Their constitution, so far as known, is represented by the 
following formulas, in which it is shown that quinin differs from 
cinchonin by the substitution of methoxyl, CH s O for H: 



CH C.C 10 H 15 (OH)N 




CH C .C 10 H 15 (OH)N 


HC / iCH 




CH 3 . C/ 


Y>- 


hc \A/ ch 

CH N 

Cinchonin. 




HC\ 


xA> 

CH N 

Quinin, 



In doses of 2 to 5 gr. (0.1-0.3 g m -) quinin acts as a stimu- 
lant, especially to the nervous system; in doses of 5 to 30 gr. (0.3- 
2 gm.) it is an antiperiodic for malarial fevers; in doses of 10 gr. 
(0.6 gm.), an antipyretic; in doses of 1 to 2 gr. (0.06-0.13 gm.), 
a general tonic. 

In overdoses it produces quinin fever, with erythema, ringing 
in the ears, hemorrhage into the labyrinth, with deafness, tran- 
sient blindness, destruction of the blood-corpuscles, and even 
respiratory failure. 

Tests. — (1) A salt of quinin with chlorin or bromin water 
treated with excess of ammonium hydroxid gives a characteristic 
emerald-green color, due to thalleioquin. 

(2) Dilute solutions of quinin salts acidulated with sulphuric 
acid give a beautiful light blue fluorescence. A red color with 
concentrated sulphuric acid shows that other substances are present. 

Cinchonin, C 19 H 22 N 2 0, is found with quinin in almost all the 
cinchona barks. It is a white, bitter, crystalline alkaloid, resem- 
bling quinin in ordinary properties, though medicinally much less 
effective. It is a quinolin derivative, as stated above. 



5IO CYCLIC COMPOUNDS 

The doses of the cinchonin salts are about double those of the 
quinin salts. 

Tests. — (i) A salt of cinchonin with chlorin or bromin water 
yields a yellowish white precipitate insoluble in ammonia. 

(2) A neutral solution of cinchonin gives with potassium ferro- 
cyanid a white precipitate soluble in excess. This solution in 
excess, treated with an acid, yields a golden yellow precipitate. 

Strychnin (C 21 H 22 N 2 2 ). — This alkaloid, accompanied by 
brucin, is contained in the seeds of Strychnos nux vomica and dif- 
ferent plants of the same genus. They are usually extracted 
from nux vomica, which contains from 3 to 4 per cent, of alka- 
loids. 

Properties. — Strychnin crystallizes in white, rhombic prisms, 
without odor, but with an intensely bitter taste. It is very spar- 
ingly soluble in water, but sufficiently so to impart a bitter taste 
even when the amount is only 1 : 700,000. It is more soluble in 
acidulated water and in chloroform. 

Both strychnin and brucin are strong monacid bases, forming 
salts, many of which are soluble in water. An official salt is the 
sulphate, (C 21 H 22 N 2 2 ) 2 H 2 S0 4 , 5H0O. This crystallizes in rectan- 
gular prisms, is soluble in water and alcohol, and is intensely bitter. 

While little is known of the constitution of strychnin, it is con- 
sidered to be a tertiary base, and as quinolin is a product of its 
distillation with potash, it is probably a derivative of quinolin. 

Medical Uses. — Strychnin is a bitter tonic, stimulating reflex 
activity, and in large doses causing tetanic convulsions. It aug- 
ments the force of the heart's action, raises blood-pressure, in- 
creases the depth and frequency of respiration. Dose of strychnin 
or its salts: -^ to yL gr. (0.001-0.005 gm.). 

Toxicology. — Poisonous Symptoms. — The most marked effects 
are the convulsions, which at first are clonic (intermittent), but as 
the intervals become shorter and the paroxysms longer eventu- 
ally become tonic (tetanic). The mouth is drawn in the risus 
sardonicus, and the body usually bent back so as to rest on the 
heels and occiput (opisthotonos). The spasms of the diaphragm, 
drawing upon the ensiform cartilage, cause epigastric pains. The 
contractions of the respiratory muscles produce a sense of suffo- 
cation which may end in asphyxia. The mind remains clear to 
the last; the pupils contract during the paroxysm. The reflex 
excitability is so great that a loud noise or the touch of a medi- 
cine glass to the lips brings on a convulsion. Vomiting is readily 
induced and persists when once excited. 

Should a paroxysm last too long, asphyxia may cause death. 
Many repetitions of the painful spasms may cause death in the 
intervals, as the result of exhaustion. 



BRUCIN 511 

Fatal Period. — As a rule, the symptoms appear in less than 
twenty minutes after administration, but may be delayed for an 
hour. Usually, if the dose be very large, death occurs within two 
hours, sometimes in a few minutes. There are cases of death 
occurring as long as six hours after taking the poison. 

Fatal Dose. — The smallest amount known to have caused death 
is i gr. On the other hand, a dose of 20 gr. has been taken and 
did not prove fatal. 

Treatment. — After the inhalation of chloroform to control the 
spasms, the stomach tube may be introduced, and protected by a 
wooden wedge between the teeth. Warm water containing potas- 
sium permanganate, 4 gr. in n fl. oz., should be used freely to 
wash out the stomach. In the absence of a tube, emetics of 
mustard or zinc sulphate should be given, or hypodermics of apo- 
morphin. Chloral hydrate in 30-grain doses should be given by 
the rectum, and retention insured by giving chloroform or amyl 
nitrite inhalation. Gentle narcosis and perfect quiet are desirable. 

Detection. — (1) If strychnin be present in amounts to be recog- 
nized by chemical tests, a bitter taste will be perceptible. If this 
taste be absent, no other tests will show strychnin. 

(2) A small quantity on a white dish dissolves in a little con- 
centrated sulphuric acid without color. 

] A small portion of powdered potassium dichromate dusted 
over the above solution in sulphuric acid produces a transient 
blue, then an intense violet color, which gradually changes to 
bright red, then to rose pink, and lastly to yellow. This reaction 
is sufficiently delicate to reveal 1 : 50,000. 

Fallacy. — A mixture of morphin or heroin with 10 per cent, of 
hydrastin gives with this test a similar play of colors. 

(4) Sonnenschein's reagent, cerosoceric oxid. is first made by 
heating cerium oxalate to redness and then dissolving it in 30 parts 
of sulphuric acid. A fragment of strychnin stirred into a drop 
of this solution causes a play of colors — blue, violet, and red. 

Physiologic Test. — When a small frog is immersed in a solution 
of strychnin, or when a hypodermic injection of it is given to frogs 
or white mice two weeks old, muscular twitchings and convulsions 
are produced, ending in tetanic rigidity and death. 

Brucin 1 C 23 H 2Pj X 2 0.. 4H0O .— This alkaloid is found with 
strychnin. It is obtained in colorless prismatic crystals, slightly- 
more soluble in water and alcohol than strychnin, readily soluble 
in chloroform and amyl alcohol. It resembles strychnin in being 
intensely bitter, a strong monacid base, and a spinant poison, 
though its physiologic energy is only one twenty-fourth of that of 
strychnin. It is a tertiary base, forming salts which are soluble 
and crvstalline. 



512 CYCLIC COMPOUNDS 

Medical Uses. — It is a bitter tonic. Dose: 0.08 to 0.5 gr. 
(0.005-0.03 gm.). 

Tests. — (1) A solution of brucin treated with nitric acid gives 
a solution having a deep red color, which when warmed turns 
yellow. If a reducing agent be added, such as a crystal of stan- 
nous chlorid or of sodium thiosulphate, the color changes to an 
intense violet. 

(2) A concentrated brucin solution treated cautiously with 
drops of chlorin water gives a bright red color, changing to violet. 
Excess of chlorin water decolorizes it, and ammonia turns it brown. 

PHENANTHRENE ALKALOIDS 

When the unripe heads of certain kinds of poppy (Papaver 
somnijerum) are incised, a juice exudes and dries to a brown 
paste, called opium. Opium contains at least seventeen different 
alkaloids, of which the most important is morphin. Others worthy 
of mention are codein, narcotin, thebain, and papaverin. They 
all exist in combination, partly with sulphuric acid, but mainly 
with meconic acid. This is a hydroxydicarboxylic acid of the fatty 
series, having the formula C 5 H0 2 (OH)(COOH) 2 . It can be ob- 
tained as crystals, and is detected by the intense dark-red color 
given with neutral ferric chlorid, the color persisting after treatment 
with mercuric chlorid or boiling with hydrochloric acid. 

Opium occurs in masses or powder of a chestnut brown color, 
a narcotic odor, and a bitter taste. The crude drug should contain 
not less than 9 per cent, of morphin, and dry powdered opium not 
less than 12 per cent. Morphin is the active narcotic principle 
in all the official preparations of opium and in various proprietary 
anodynes and carminatives, such as Mrs. Winslow's, Dalby's, 
Battle's, also in nepenthe, chlorodyn, and most opium cures. 

The dose of powdered opium of standard morphin strength re- 
quired to narcotize is 5.6 times as much as that of morphin sulphate. 

Morphin (C 17 H 19 N0 3 ). — The free base takes 1 molecule of water 
of crystallization to form colorless prisms. Slightly soluble in 
water and cold alcohol, it dissolves easily in potash and soda, to 
be precipitated again on the addition of an acid. This behavior 
is due to the presence of phenolic hydroxyl, which group is the 
cause of the blue color reaction with ferric chlorid. It contains 
another hydroxyl group which is alcoholic. Morphin boiled with 
zinc dust yields pyridin, quinolin, phenanthrene, and other sub- 
stances showing it to be a polynucleated compound. When one 
of its hydrogen atoms is replaced by methyl, the product is codein. 
Codein is soluble in water, alcohol, and ether, and readily forms 
salts with acids. As a hypnotic the dose is twice as large as that 
of morphin, being J-i gr. (0.03-0.13 gm.). 



MORPHIN 



513 



Dionin is dimethyl morphin hydrochlorid, and like codein. 

Heroin, used as a substitute for codein, is diacetyl morphin, 
or the acetic ester of that alkaloid. Used for coughs, dose: ^y-J gr. 
(0.01 gm.). 

Apomorphin, C 17 H 17 N0 2 , is prepared by heating morphin with 
hydrochloric acid in a sealed tube to 140 C. (252 ° F.) for three 
hours. The chlorid occurs in colorless crystals turning greenish 
by exposure to light. Soluble in 7 parts of water, it is used hypo- 
dermically as an emetic in five drops of a 2 per cent, solution. 

Morphin is a monacid base, forming well-defined salts with 
the acids. While the hydrochlorate and acetate are official, the 
salt commonly used is the sulphate, (C 17 H 19 N0 3 ) 2 H 2 S0 4 , 5H 2 0. 

Morphin sulphate is dispensed in white, snowy needles, odorless 
and bitter. It is readily soluble in water and moderately so in 
alcohol, giving a neutral reaction. Dose: J to J gr. (0.008-0.03 
gm.). One-sixth of a grain is equal in anodyne and narcotic prop- 
erties to 1 gr. of opium. Cases of intense pain usually require 
several doses of J gr. hypodermically. 

Toxicology. — Symptoms. — The poisonous effects of a dose by 
the mouth begin to show in about twenty minutes. A hypoder- 
mic dose causes drowsiness earlier and some relief of pain in five 
minutes. There is an initial stage of exhilaration with strength- 
ening of the pulse. This soon ends in giddiness, languor, som- 
nolency, nausea, itching of the skin, and slow, full pulse. The 
pupils are contracted to the size of a pin's head, and are not 
influenced by light and darkness. There are shallow and stertor- 
ous respirations, with peculiar death-like pauses lasting half a 
minute, alternating with periods of about thirty irregular respira- 
tions. 

The breathing may not have this rhythmic character, but may 
pass gradually and calmly to feeble and slow breathing, asphyxia, 
and death. As the respiration is disturbed, the surface grows blue, 
cold, and damp; the urine is retained. As death approaches, the 
coma is profound, the pulse becomes weak, and the pupils may 
dilate. 

Anomalous cases are reported in which convulsions occur; spon- 
taneous vomiting and diarrhea have been known to eject the poison 
and save the patient. Very rarely the pupils have not been con- 
tracted. Relapse into coma and death has happened even after 
the patient has recovered consciousness. 

Fatal Period. — Death has occurred in forty-five minutes, and, 
on the other hand, has supervened after the lapse of four days. 
In most of the fatal cases life is prolonged from six to twelve hours. 
If breathing can be kept up for forty-eight hours, recovery is highly 
probable. 

33 



514 CYCLIC COMPOUNDS 

Fatal Dose. — Most persons not habituated to opium would die 
after 5 to 10 gr. of opium or 1 to 2 gr. of morphin. There are per- 
sons highly susceptible who are poisoned by doses of less than 1 
gr. of morphin; while, on the other hand, there are those habituated 
to the use of opium who not only survive enormous amounts, but 
take daily doses ten times the fatal quantity without apparent 
injury. 

Treatment. — The stomach should be washed out with the siphon 
tube, using water containing potassium permanganate, 20 gr. to 
the tumblerful. This agent promotes morphin oxidation. If this 
be not procurable, the washing may be done with infusions of tea 
or tannic acid, or mixtures of powdered animal charcoal and water. 
Emetics of mustard may be given in 1 or 2 doses of a teaspoonful 
each, or zinc sulphate, 20 to 30 gr. A prompt emetic given 
hypodermically is apomorphin, 5 to 10 min. of a 2 per cent, solution. 
When the permanganate is given subcutaneously, it forms with 
the serum of the blood an albumin manganic oxid which has the 
power of decomposing the morphin. Solutions of 0.5 per cent, 
strength (1 gr. in 2 fl. oz.) may be injected in amounts of 1 to 6 
fl. dr. at two or three points. 

The symptoms to be combated are failure of respiration at first, 
and later on the weakened action of the heart. Somnolency itself 
is not important if the patient's breathing be sustained. In time 
the poison will be oxidized or eliminated. To stimulate respira- 
tion it may be necessary to make the patient conscious of his needs 
by shouting in his ear, by shaking, flogging with a wet towel, 
applying electricity to the cutaneous surface intermittently, or 
by moderate walking. A good rate of respiration must be kept 
up even if resort must be had to the method of artificial movements 
of the arms. Of use may be found hypodermic doses of strychnin, 
■fa gr., cocain hydrochlorate, J gr., or atropin sulphate, -gL- gr. 
To stimulate the heart in the later stages, coffee and brandy are 
indicated. 

Postmortem Appearances. — The autopsy does not reveal any 
local action on the mucous membranes of the alimentary tract. 
Neither can any characteristic lesion be discovered elsewhere. 
Generally there are found fulness of the cerebral vessels, menin- 
geal effusions, and congestion of the lungs. 

Tests. — Many of the tests are based upon the readiness with 
which morphin is oxidized and the colored products obtained by 
different degrees of oxidation. These are pseudomorphin and 
compounds of morpholin and phenanthrene. 

Le]orVs Iodic Acid. — Upon a fragment of the morphin on a 
dry white dish is placed a drop of a solution of iodic acid, and the 
dish is then set aside for ten minutes. If the brown color of free 



VERATRIN 515 

iodin appear, the spot is dried and, with chloroform, the iodin is 
washed off until no color remains. (The chloroform residue will 
turn blue with starch.) After drying the washed spot it is wet 
with a drop of 10 per cent, ammonia water, which, reacting with 
morphin oxidation products, gives a mahogany color. 

Delicacy. — A definite reaction is obtained with -g-^j- gr. 

Ferric Chlorid. — A fragment of the solid or the residue sus- 
pected is moistened on a white dish with neutral ferric chlorid sol- 
ution. A blue color appears, which may be greenish if excess of 
ferric chlorid has been used, destroyed by alcohol. The color 
is probably due to a phenol compound of a ferrous base. This 
reaction is given with many aromatic compounds containing the 
phenolic hydroxyl, but no other ordinary alkaloid gives it. The 
morphin blue is changed to orange and yellow by nitric acid. 

Frohde's Molybdic Acid. — The reagent is a freshly made solu- 
tion of 1 or 2 mg. of molybdic acid or ammonium molybdate in 
1 c.c. of sulphuric acid. The dried material on a white dish is 
treated with 1 drop of the reagent. A purple color, changing to 
violet and green, indicates morphin. As other alkaloids give bluish 
and greenish colorations with this reagent, it is advisable to identify 
the color by a control test on a fragment known to be morphin. 

Delicacy. — A decisive reaction is given by 6 * 00 gr. 

Sulphuric and Nitric Acids. — A trace of morphin on a white 
dish is touched with a drop of concentrated sulphuric acid; a 
colorless solution is formed. After standing for fifteen hours this 
solution is treated with a trace of nitric acid, which gives a bluish- 
violet color, changing to blood red. 

Delicacy. — This reaction is decided with 0.0 1 mg. of morphin. 

ALKALOIDS OF UNKNOWN CONSTITUTION 

Veratrin. — This name, according to the U. S. Pharmacopeia, 
covers a mixture of alkaloids obtained from the seed of Asagrcea 
officinalis. It is a white, inodorous powder, soluble in water and 
alcohol. An important part of this mixture is the alkaloid cevadin 
or crystallized veratrin (C 32 H 49 N0 9 ). Another alkaloid present is 
jervin (C 26 H 37 N0 3 ), with traces of amorphous veratrin. Like the 
aconite alkaloids, these are quinolin derivatives. 

Dose of fluidextract of veratrum viride (American hellebore): 
1 to 3 min. (0.06-0.18 c.c). It is a powerful cardiac depressant. 

Toxicology. — Symptoms. — Poisonous doses of veratrum viride 
or veratrin cause nausea, vomiting, abdominal pain, weakness, 
feeble pulse, giddiness, loss of sight, dilated pupils, drowsiness, 
coma, with death from asphyxia. 

Fatal Dose. — The fluidextract has been fatal in doses of 70 min. 
(4.3 c.c). 



516 CYCLIC COMPOUNDS 

Treatment. — The stomach should be thoroughly washed out 
by the siphon tube, or emetics employed. Tannic acid or vege- 
table astringents will precipitate the alkaloid. Cardiac depres- 
sion may be combated with atropin or strychnin, or brandy hypo- 
dermically. The posture should be recumbent, and artificial 
respiration used if necessary. 

Tests. — (i) Veratrin (U. S. P.) in dry fragments on a white 
plate dissolves yellow in concentrated sulphuric acid. On stand- 
ing the yellow solution changes to bright red, and later on to a 
darker red or crimson, which persists for hours. 

(2) Veratrin dissolves in hydrochloric acid and on boiling 
develops a persistent bright red color. 

(3) One part of veratrin rubbed with 6 parts of cane-sugar is 
treated with a few drops of strong sulphuric acid. The color de- 
veloped is yellow, then green, and finally blue. 

(4) Physiologic Test. — The pto mains which give color products 
like those described above do not have the same effects on a live 
frog. Hypodermic injection of veratrin causes vomiting, slow 
pulse, convulsions, and death. 

Gelsemin is a poisonous alkaloid of Gelsemium sempervirens, the 
yellow jessamine or jasmine. It is a white, very bitter, inodorous 
powder, used in medicine as a nervous and arterial sedative. In 
overdoses it is a violent poison. The fluidextract of the root is 
given in doses of 2 to 10 min. (0.12-0.65 c.c). The dose of the 
alkaloid is -g^ to 3V gr. (0.001-0.002 gm.). 

Gelseminin is a brownish alkaloid separable from the same plant. 

Toxicology. — Symptoms. — The poisonous effects are shown by 
falling of the eyelids, double vision, dilated pupils, great muscular 
weakness, depression of the temperature, pulse, and respiration. 
Death is by asphyxia, the mind remaining clear. 

Fatal Dose. — Three teaspoonfuls of the fluidextract have caused 
death. The symptoms appear promptly, and death may follow 
in an hour or be delayed eight hours. 

Treatment. — After the stomach has been thoroughly washed 
out stimulants are given, and hot applications made to the epi- 
gastrium and extremities. Digitalis will strengthen the heart and 
atropin the respiration. 

Tests. — The alkaloids, when touched with concentrated alcohol 
on a white plate, yield a yellow-brown color. A fragment of potas- 
sium chromate or cerosoceric oxid changes the color to red and 
purple, the final color being green. 

Physiologic Test. — Administered hypodermically to frogs, cats, 
or rabbits, the alkaloids cause prostration, convulsions, dilated 
pupils, and asphyxia. 



PTOMAINS 517 



PTOMAINS 



Not infrequently cases of poisoning occur from eating foods 
of animal origin — such as meats, fish, cheese, milk, custards — 
that have become unwholesome from the products of bacterial 
growth. These products are considered as belonging to one of 
the two classes, ptomains and protein toxins. Leukomains con- 
stitute a class of substances, such as the purin bases and creatins, 
some of which are poisonous, and all of which are produced by 
the normal breaking down of tissue in the living body, or, in other 
words, the splitting of protein by enzyms secreted by the body cells. 
Auto-intoxication, or self-poisoning, such as "biliousness" or 
uremia, is the result either of the abnormal formation of ptomains 
or of the undue accumulation of leukomains in the body. The 
leukomains, when not duly oxidized to urea, C0 2 and H 2 0, often 
cause serious disturbance of health, and the ptomains and toxins 
are sometimes highly toxic. If the phosphorized fat, lecithin, be 
acted on by putrefactive bacteria, cholin may be split off as a 
ptomain. If the same cleavage be done during life by the body 
cells, the cholin is a leukomain, and if not normally oxidized, causes 
auto-intoxication. 

Ptomains are soluble basic bodies formed by the action of certain 
micro-organisms on putrefying protein material. The amino- 
acids ornithin and lysin, constituents of pure proteins, subjected 
to bacterial action, split off C0 2 and change to putrescin and 
cadaverin (p. 500). Some of them are active poisons, but others, 
like the methylamins and ethylamins, are harmless. They are 
alkali-like in some respects, and hence were formerly termed cad- 
averic alkaloids. They are strongly basic and combine with acids 
to form salts. Like the proteins from which they are derived, they 
are precipitated with the chlorids of mercury, gold, and platinum; 
with picric acid, tannic acid, phosphomolybdic acid, and phospho- 
tungstic acid. Having these reactions in common with vegetable 
alkaloids, they may be considered as related to them. However, 
many of them differ from true alkaloids in constitution, having 
their nitrogen in an open-chain molecule of the fatty series, and 
belonging to the class of amins (p. 497).. These ptomains, which 
do not contain a closed chain (acyclic), are subdivided into those 
free from oxygen and those containing that element. The acyclic 
free from oxygen comprise the methylamins, butylamin, amylamin, 
neuridin, saprin, cadaverin, putrescin, spermin, mydalein. The 
acyclic ptomains containing oxygen include cholin, neurin, mus- 
carin, betain, gadinin, mytilotoxin, and a few others. 

In the following list are included the ptomains which have the 
nitrogen in a closed chain (pyridin ring) like true alkaloids (cyclic), 



518 CYCLIC COMPOUNDS 

and those as yet unclassified: collidin, parvolin, corindin, morrhuin, 
asellin, typhotoxin, tetanin, spasmotoxin, tetanotoxin, pyocyanin, 
tyrotoxicon. 

Of the above list, a small number of ptomains are known to 
be injurious in foods. These are tyrotoxicon of milk, cream puffs, 
ice cream, and cheese; mytilotoxin of mussels and oysters; muscarin 
of mushrooms and meat; and from spoiled fish and meat, cholin, 
neuridin, neurin, cadaverin, putrescin. While they are decom- 
position products of protein, apparently they may be engendered 
in tissues still living, such as fresh oysters and mussels. To pro- 
duce them is required a certain favorable combination of special 
micro-organisms, protein, air, and temperature. They are un- 
stable, changing in a short while through many stages. In most 
cases decomposition has not gone far enough to make the food 
offensive. The toxicity may be great when there is no taint per- 
ceptible to smell or taste. 

Symptoms. — These make their onset soon after eating the 
poisoned food. They may be described broadly as the symptoms 
of gastro-enteritis, with depression and other nervous disturbances. 
There are in most cases marked thirst, salivation, nausea, vomiting, 
abdominal pain, diarrhea, cramps in the legs, great prostration, 
chills, feeble pulse, dilated pupils, drowsiness or delirium, numb- 
ness, paralysis, exhaustion, and collapse. 

Sometimes the postmortem reveals inflammation of the stomach 
and bowels, though fatal cases occur which are free from morbid 
changes. 

Cholin (C 15 H 15 N0 2 ) (bilineurin) is a complex amin occurring 
in the bile of animals, in the human placenta, in the yolks of eggs, 
in hops, and in fungi. 

Cholin is formed by treating an aqueous solution of trimethyl- 
amin with ethylene chlorhydrin: 

N(CH 3 ) 3 + C 2 H 4 C10H f H 2 = C 3 H 4 OHN(CH 3 ) 3 OH + HC1. 

Cholin. 

The lecithins of the animal corpse produce cholin during the 
first forty-eight hours of putrefaction. On and after the third 
day cholin diminishes, while other closely related bodies, such as 
neuridin, putrescin, and cadaverin (ptomains), appear and increase 
daily. Muscarin can be made by oxidizing cholin with nitric acid. 
The effect of heat is to split cholin into glycol and trimethylamin. 

Properties. — It is a syrupy fluid, soluble in water and alcohol, 
and strongly alkaline. It absorbs carbon dioxid from the air like 
other strong bases, and forms a hydrochlorid which crystallizes 
in plates like cholesterin. In large doses its action is poisonous. 



MUSCARIX 519 

Lecithin is a complex body commonly found in yolk of egg, 
brain and nerve tissue, blood, pus, milk, etc. The several varieties 
are compounds of cholin and glycerophosphoric acid with the 
acids of fat. This composition is shown by the following formula 
which gives glyceryl united to two stearic acid groups and one of 
phosphoric acid, linking the cholin: 

f O . QsH^O 
C 3 H 5 . O.QsH^O //(CH 3 ) 3 
(O.PO3H. C 2 H 4 N-OH. 

With alkalis they saponify, yielding the fatty acids, the glycero- 
phosphoric acid, and cholin. Like the true fats, they are soluble 
in ether. 

Neurin, C 5 H 13 XO, is an amin derivative occurring as a prod- 
uct of decomposition in the tissues of the brain and suprarenal 
capsule. It is one of the ptomains of muscular tissue. It can be 
formed by boiling cholin with baryta water and thereby abstracting 
the elements of water: 

C 2 H 3 OHN(CH s ) 3 + H,0 = C 2 H 4 OHN(CH 3 ) 3 OH 

Xeurin. Cholin. 

It is a poison much more powerful than cholin, the symptoms 
resembling those of obstruction of the bowel, with nausea, pain, 
and depression. 

Diamins. — This class of compounds, containing two XH 2 groups, 
has several representatives, basic in character, among the putrid 
products, viz.: trimethylenediamin, H 2 N . (CH 2 ) 3 NH 2 , found in 
the cultures of comma bacillus; tetramethylenedia min , or putrescin, 
H 2 X . (CH 2 ) 4 NH 2 , found in cultures of comma bacillus and putrid 
flesh; pentamethylenediamin or cadaveri)i, H 2 N . (CH 2 ) 3 NH 2 , occur- 
ring in the later stages of putrefaction, after cholin has disappeared, 
as a basic liquid with a disagreeable odor; nenridin, isomeric with 
cadaverin, and produced with cholin as an early putrid product; 
mydalein, a diamin of unknown structure, product of putrefaction, 
actively poisonous, causing dilated pupils, diarrhea, convulsions, 
and paralysis. 

Amanitin (CH 3 . CHOH . X . OH . (CH 3 ) 3 ) (isocholin) occurs 
as an alkaloid in the red, fleshy mushroom, Agaricus muscariics, 
or jiy agaric, which is poisonous to flies and man. It is isomeric 
with cholin, and can be prepared by introducing methyl into 
aldehyd ammonia. Nitric acid oxidizes it to muscarin. 

Mliscarin, CH 2 CH(OH) 2 OHX . (CH 3 ) 3 , is found in the mush- 
room, Agaricus muscarius, and is also a ptomain. Chemically, 



520 CYCLIC COMPOUNDS 

it is related to amanitin, neurin, and cholin, and can be produced 
synthetically from the latter. 

Properties. — When dry, it occurs in odorless and tasteless, 
irregular crystals, which deliquesce to form a syrupy liquid, strongly 
alkaline, soluble in water and in alcohol, insoluble in chloroform 
and in ether. It can be reduced to cholin and oxidized to betain. 
It breaks up into trimethylamin. Precipitated by excess of plati- 
num chlorid, it forms octahedral crystals, while the chlorplatinate 
of cholin crystallizes in plates. 

Toxicology. — Symptoms. — Muscarin is far more poisonous than 
cholin or neurin, and is the active cause of the symptoms of mush- 
room poisoning. These are vomiting, griping pains in the stomach 
and intestine, slow pulse, ending in arrest of the heart's action; 
contraction of the pupils, salivation, and fatal collapse. Alarming 
symptoms may follow -gL- gr. (i mg.). 

Treatment. — Its physiologic antagonist and antidote is atropin. 
Stimulants, morphin, and strychnin are also of service. 

TOXINS 

Toxins are poisonous bases produced in the animal body by 
certain bacteria, which also cause infectious diseases. Such are 
diphtheria toxin, typhotoxin of typhoid fever, tetanin, and spasmo- 
toxin of tetanus. 

Food Toxins. — The protein toxins that cause food poisoning 
are either — (i) the poisonous products of specific bacteria, not 
putrefactive, growing in the meat after slaughter; or (2) they are 
products of specific bacteria infecting the tissues of the food animals 
before slaughter. 

(1) A common form is botulism or sausage poisoning, caused 
by the Bacillus botulinus contaminating ham, sausage, and fish. 
Other powerful toxins have been developed by certain species of 
bacteria, like Proteus vulgaris, growing in pork and beef sausages. 
Sausage poisoning manifests itself usually within twenty-four hours, 
sometimes as soon as half an hour, though the onset may be de- 
layed for a week. 

The symptoms of sausage poisoning are epigastric discomfort, 
belching, nausea, vomiting, gripes, diarrhea, followed by consti- 
pation. After a few days the nervous symptoms appear: dilated 
pupils, blindness, falling of the lids, paralysis of the tongue and 
pharynx, and loss of voice. The secretions may be suppressed, 
the pulse irregular, and the muscles weak to exhaustion. In a few 
cases there are somnolence, giddiness, convulsions, paralysis, and 
possibly acute nephritis. Death may follow delirium and coma, 
or a favorable turn may lead to slow recovery after many days. 






TOXINS 521 

The postmortem appearances have been in the nature of hyper- 
emia of meninges, lungs, spleen, kidneys, liver, and alimentary 
tract. Nothing has been found characteristic of botulism. 

(2) The toxins of the other class result from the activities of 
the pathogenic bacteria before the animals are killed. The meat 
from cows and calves that have had pyemia, septicemia, or specific 
enteritis will cause symptoms something like arsenic poisoning, 
cholera, or typhoid fever. These are headache, vomiting, profuse 
diarrhea, gripes, chills, and fever. 

Treatment. — The efforts of nature to remove the poison should 
be promoted by free potations of warm water and salt, followed 
by mild laxatives and high irrigation of the intestines with enemas. 
Excessive vomiting, purging, and pain are to be relieved by hypo- 
dermic injections of morphin. Stimulants are needed, and sub- 
cutaneous injections of normal salt solution will be helpful. 

Resemblances Between Ptomains, Toxins, and Vegetable 
Alkaloids. — A study of the symptoms narrated above shows certain 
points of resemblance to the symptoms caused by alkaloidal poisons. 
For example: somnolency may be mistaken for the effects of 
morphin; dilated pupils and delirium are prominent signs of poison- 
ing from plants yielding atropin; paralysis, numbness, convulsions, 
and stupor may be found after doses of conium and gelsemium. 

The chemical tests dependent on color changes due to oxidiz- 
ing agents, when applied to vegetable alkaloids, give results closely 
resembling those caused in certain ptomains, so that mistakes 
have occurred in the work of expert chemists. The symptoms of 
the case, the physiologic tests on lower animals, and all known 
chemical tests must be studied and harmonized before the analyst 
can be certain that he is not dealing with ptomains, but that he 
has detected morphin, atropin, coniin, nicotin, strychnin, veratrin, 
or colchicin. 

The various methods employed for separation of the alkaloids 
are none of them perfectly successful in excluding the ptomains. 
Perhaps the best yet devised is that known as the — 

Kippenberger Process. — Separation is accomplished by virtue 
of the mixture of tannic acid and glycerin, which dissolves the 
vegetable alkaloids, but leaves ptomains and toxalbumins undis- 
solved. The alkaloids are separated from one another by shaking 
the liquid with successive immiscible solvents in a separating funnel 
with a stopcock (Fig. 83). Each solvent extracts a group, which 
is left on evaporation of the solvent, and the alkaloid is detected in 
the residue by appropriate tests. 

The material, finely minced, is macerated at 40 ° C. (104 ° F.) 
in a 10 per cent, solution of tannic acid in glycerin for two days. 
It is then put in a bag of straining cloth and the fluid part pressed 



522 CYCLIC COMPOUNDS 

out. This fluid part is heated to between 6o° C. (140 F.) and 
70 C. (158 F.) for two hours; cooled and filtered. The filtrate is 
shaken with petroleum ether, which separates the fats. Any petro- 
leum ether not separated from the liquid is removed by evaporation 
on a water-bath, and the liquid is now shaken with chloroform while 
still acid. This chloroform-acid extract removes aconitin, can- 
tharidin, colchicin, digitalin, jervin, narcotin, picrotoxin, and traces 
of strychnin, veratrin, brucin, delphinin, and narcein. The liquid, 
made alkaline with potassium hydroxid, is again shaken with 
another portion of chloroform, which now removes apomorphin, 
atropin, brucin, codein, coniin, emetin, nicotin, pilocarpin, spartein, 
strychnin, veratrin. Potassium bicarbonate is now added to 
change any excess of hydroxid to carbonate, and the mixture shaken 
with chloroform containing 10 per cent, of alcohol, which extracts 
morphin and narcein. The liquid is lastly saturated with sodium 
chlorid and shaken with chloroform containing 15 per cent, of 
ether, which removes strophanthin. 

Infection Toxins.— In the cells of bacteria are built up 
poisonous substances which may be retained or may pass out by 
diffusion. The filtrate of a culture of diphtheric bacilli is poisonous 
because of the soluble toxin excreted by the bacilli. In a few days 
toxemia is produced by absorption of toxins from the diphtheric 
membrane in the throat. 

The filtrate of a typhoid culture is harmless because the toxin 
has been retained by the typhoid bacillus. But if the precipitated 
bacilli be dried, pulverized, and suspended in water, the intracel- 
lular toxin is liberated and the mixture is poisonous. In the period 
of invasion of typhoid fever the bacilli find access to the circulation 
and multiply there. As they die from day to day, their intracel- 
lular toxins are set free and cause the fever of a septicemia or 
bacteremia until the bacilli are all gone. 

Antitoxins. — When the body is infected by a toxin a defen- 
sive protein of unknown composition is formed in the blood, which 
combines with and neutralizes the toxin. The antitoxin of diph- 
theria is produced artificially by injecting horses with a culture of 
the diphtheria bacilli. By gradually increasing doses the animal 
acquires immunity, and its serum, drawn from the vessels, is so rich 
in the antitoxin that when injected into man it gives immunity from 
or cures the infection of diphtheria. 

Agglutinins, Precipitins, and Lysins.— When the body is in- 
jected with certain bacteria or cells, antibodies are developed in 
the blood. These bodies cause a reaction when they are mixed 
with the special injected material. 

Agglutinins. — The blood-serum of a case of infectious disease 
contains agglutinin, which has the property of clumping together 



OPSONINS 523 

the specific bacteria in a culture. Thus, in Widal's test for typhoid 
fever, blood from the patient is added to a fresh culture of typhoid 
bacilli, and if the case be typhoid fever, the bacilli adhere in tangled 
masses. They are not killed, but held in check, so that they do 
not multiply and are more easily exterminated. 

A precipitin is an antibody which acts as a protective against 
foreign proteins in the blood. It confers upon the serum the 
special property of precipitating from solution the protein that 
excited its production. , 

Lysins are cell-destroying substances developed in the serum by 
the injection of non-fatal doses of bacteria or their products. Bac- 
ieriolysins are bacteria-destroying, soluble proteins of the blood 
plasma. Hemolysins are able to destroy the red blood-cells of 
another species of animal. An autolysin destroys cells in the 
animal's own body; a homolysin, those in an animal of the same 
species; a heterolysin, those in an animal of different species. 
These lysins consist of two substances called the immune body and 
the complement. The lysins cannot act upon their objects of attack 
without an intermediate substance. This substance, the immune 
body, has two chemical affinities: (1) It is specific for each lysin 
that is developed, and (2) it acts by uniting with the bacterial 
product on the one hand and the blood complement on the 
other. 

Opsonins {caterers) are certain elements of blood-serum, differ- 
ent from lysins and antitoxins, which unite chemically with invading 
bacteria and alter them so that the leukocytes can phagocyte and 
destroy them. Each variety of disease germ has its corresponding 
opsonin. The amount of opsonins in the blood of an individual 
determines his susceptibility to bacterial invasion. To measure 
this resistance of the patient, as compared with that of a healthy 
person, is to find out his "opsonic index." 

To do this, cultures are made of a mixture of the serum of the 
patient's blood with washed leukocytes and emulsion of the specific 
bacteria. At the same time a control experiment is made with 
normal blood-serum. The average of germs to leukocytes is 
counted and compared in the two experiments. The result is 
stated as high, normal, or low opsonic index. Cases of bacterial 
infection with normal or low index are treated by inoculating the 
patient with a vaccine of the specific bacteria, watching the opsonic 
index. By this means it is intended to stimulate the tissues to an 
increased production of opsonins until the level is maintained 
higher than normal and the invading bacteria are disposed of. 



524 



CYCLIC COMPOUNDS 



PROTEINS OR ALBUMINOUS MATTER 

The compounds considered under this head are the post- 
mortem representatives of the protoplasm which constitutes the 
indispensable basis of life in plants and animals. The animal 
body is especially rich in these proteins or albuminous substances, 
as they are sometimes called. Apparently, they are all formed 
originally by plants only. Animals take the fundamental structure 
in vegetable food and afterward make some changes in them, 
but do not make them by synthesis of their elements. 

They belong to the class of colloids, as most of them do not crys- 
tallize nor diffuse through the membrane of a dialyzer without 
difficulty, owing to the large size of the molecule. They are non- 
volatile; without odor or taste; some are soluble in water, others 
are insoluble; all of them are optically active, turning the polarized 
ray to the left. All of them contain carbon, hydrogen, oxygen, 
nitrogen, and traces of mineral salts. Other constituents found 
in some of them are sulphur, phosphorus, and iron. 

It is not known if their constitution be definite; it is certainly 
very complex. The great number and variety of proteins in 
plants and animals is explained by the fact that many of them 
contain as many as ioo asymmetric carbon atoms (p. 425), thus 
permitting special isomerids, enormous in number, and possible 
modifications of properties to an unlimited extent. These differ- 
ences in spatial arrangement of the atoms are frequently of greater 
importance for the direction of vital processes than coarser differ- 
ences in chemical structure. 

By blending certain amino-acids Fischer has succeeded in pro- 
ducing artificially polypeptid bodies having some resemblance to 
peptones in properties and reactions, but no structural formula 
can be made to represent pure protein. Ignorance of their true 
constitution is the excuse for a classification less accurate than is 
desirable, based upon their differences in behavior when heated, 
when treated with acids and alkalis, and when salted out. Some 
of them exist already formed in the animal tissues and fluids, and 
are sometimes referred to as native proteins (albumins, globulins, 
nucleo-albumins). Others are products of the action of heat and 
chemicals or of enzyms upon the native proteins, and hence are 
referred to as derived proteins (albuminates, proteoses, peptones). 

The simple proteins, albumin and globulin, are present in all the 
fluids and solids of the body except the tears and sweat. Their 
molecular weights have been estimated as above 10,000, and while 
they are believed to be variable in size, all are very large, their per- 
centage composition averaging as follows: carbon, 52; hydrogen, 
7; nitrogen, 16; oxygen, 22; sulphur, 1; phosphorus, 0.5. 






PROTEINS 525 

Decompositions. — By the action of hydrochloric acid the nitro- 
gen of the proteins is divided among three fractions of the mole- 
cule: ammonia, amino-acids, and diamino-acids. Alkalis have the 
property of separating a portion of the nitrogen as ammonia. If 
the proteins be boiled with caustic alkalis, only a part of the sulphur 
goes off in a sulphid combination, the remainder being converted 
to sulphate by fusion with niter and potassium carbonate. This 
is proof that the protein molecule contains at least 2 atoms of 
sulphur. Under oxidizing agencies profound changes occur, the 
products being acids, aldehyds, ketones, amido-acids, hydrocyanic 
acid, carbon dioxid, and ammonia. 

Agents which cause hydrolysis, such as ferments and dilute 
acids, split up the simple proteins into other proteins of lower molec- 
ular weight — proteoses and peptones — which no longer coagulate 
when heated, and which, owing to the diminished size of the mole- 
cule, readily diffuse. The final products of persistent hydrolysis 
by ferments or prolonged boiling with acids are of known constitu- 
tion, are supposed to be preformed like the stones in a building, 
and in time a study of them as nuclei may lead to a knowledge of 
their mode of union in the protein molecule. They are the 
monoa mino-acids , such as leucin, glycocoll, and alanin; the amino- 
diacids, aspartic and glutamic; the diamino-acetic and diamino- 
valerianic acids (ornithin); the dipeptids, prolin and oxyprolin; 
the oxyacid, serin; the hexon bases or diamino-acids, lysin, arginin, 
and histidin; the isocyclic nuclei of tyrosin and phenylalanin; the 
heterocyclic nucleus of tryptophan; the carbohydrate nucleus, 
glucosamin; the sulphur compound, cystin. Each of these has 
the acid group CO OH at one end and the basic amino-group XH, 
substituted for a hydrogen atom on the nearest carbon atom. The 
rest of the compound may be regarded as a radical either of the 
open chain or the cyclic series. The general formula then may 
be stated as: 

/XH 2 
R-CH-COOH. 

It is possible for the acid group of one to unite with the basic group 
of another in an indefinite number of permutations. The various 
proteins have different kinds, numbers, and arrangements of these 
relatively few amino-acids. 

Putrefaction is the breaking up of proteins by the growth 
of certain bacteria, the fetid products of intestinal putrefaction 
being phenol, indol, skatol, ptomains, volatile fatty acids, methyl 
mercaptan, ammonia, and hydrogen sulphid. Part of the phenol 
and skatol are absorbed, and in the liver are joined or conjugated 
with potassium-acid sulphate, being finally eliminated by the urine. 



526 CYCLIC COMPOUNDS 

The other end-products remain for a while in the intestines and 
are ejected as feces and flatus (p. 396). 

Coagulation. — The simple soluble proteins, when acidulated 
and heated, undergo a change into insoluble material. The process 
of change is called coagulation. The original substance cannot 
be reproduced by any manipulation of this white insoluble solid,, 
which in this respect differs from a precipitated protein. The 
different proteins coagulate at different temperatures; none coagu- 
lates by heating alkaline solutions. Complete coagulation re- 
quires the combination of heat applied to an acid solution contain- 
ing 5 per cent, of neutral salts. (See Albuminuria.) 

Precipitation in an insoluble combination is produced by 
adding the mineral acids, especially nitric acid; by some organic 
acids in strong solutions of neutral salts; by potassium ferrocyanid 
with acetic acid; by acid solution of tannin; by picric acid, carbolic 
acid, salicylsulphonic acid, trichloracetic acid, by sodium tung- 
state; by phosphomolybdic acid, by potassiomercuric iodid; by 
solutions of metallic salts, such as mercuric chlorid, cupric sul- 
phate, lead acetate, and silver nitrate; by alcohol and chloral; 
by saturated ammonium sulphate, which precipitates all except 
peptone. 

Experiments. — Having made a solution of albumin by shaking 
white of egg in a bottle with five times as much water, and separat- 
ing the sediment, proceed to show coagulation by heat, acids, 
and by the other reagents named above. Using fresh portions 
each time, apply the following tests also. 

Color Reactions. — Any protein, such as the glutin in dry bread, 
will give the xanthoproteic reaction, which is the yellow color 
caused by the action of concentrated nitric acid, changing to orange 
on the addition of excess of ammonium hydroxid. This indicates 
the presence of the benzene ring, and is given by tryptophan, 
tyrosin, or phenylalanin (pp. 459 and 500). 

Biuret Reaction. — A violet to pink color obtained when a hot 
Fehling's solution is overlaid with the protein — after complete 
hydrolysis the products do not give this reaction. 

Frohde's Reaction. — A solution of molybdic acid in sulphuric 
acid gives to solid proteins a blue color (p. 515). 

Milton's Reaction. — This reagent (mercuric nitrate) imparts a 
purple-red color to pieces of solid proteins when they are boiled in 
it. It is also given by the phenol group in the tyrosin nucleus 
(pp. 457 and 500). 

Liebermann's reaction is the violet-blue color obtained when 
proteins are dissolved in boiling hydrochloric acid. 

Adamkiewicz' s reaction requires the solution of the protein in 
hot glacial acetic acid. When cool, it is overlaid with concentrated 



PROTEINS 527 

sulphuric acid. A violet or purple band appears at the line of con- 
tact. It is due to the tryptophan group (p. 500). 

Molisch's reaction (p. 473) indicates glucosamin or some other 
carbohydrate (p. 434). 

Fallacies. — The positive detection of a protein requires all 
of these color reactions. Xo one of them can be considered as 
characteristic, as similar colors are caused by alkaloids and other 
nitrogenous organic substances. 

Classification of the Proteins.— As knowledge is lacking on 
which to frame strictly chemical names, the following have been 
temporarily adopted: (1) Protamins; (2) Histons; (3) Albumins; 
(4) Globulins; (5) Scleroproteins; (6) Phosphoproteins; (7) Conjugate 
proteins (a, chromoproteins; b, glucoproteins; c, nucleoproteins); 
(8) Derivatives of Protein (a, infraproteins; b, proteoses; c, pep- 
tones; d, polypeptids). 

1. Protamixs. — In the heads of the spermatozoa of fish are found 
nucleoproteins which yield basic substances that resemble simple 
albumins in some reactions, though not in all. Their molecules 
contain the groups that give the biuret reaction and are precipitated 
like alkaloids, but not the groups that coagulate when heated and 
respond to Millon's reagent. They yield only a small number of 
amino-acids on hydrolysis. Hence they are regarded as the 
simplest of all proteins. They are called protamins and differ 
according to their source; thus, salmin (salmon), C 30 H 57 N 17 O 6 ; 
star in (sturgeon), C 34 H 71 X 17 9 , etc. When hydrolyzed by trypsin 
they first yield substances analogous to peptone called protons, and 
finally split up into simpler products, among which are bases con- 
taining 6 atoms of carbon, hexons, named histidin, C 6 H 9 N 3 2 ; 
arginin, C 6 H u N 4 3 ; and lysin, C 6 H 14 N 2 2 . As the more complex 
proteins also yield hexons, it is probable that all contain a protamin 
nucleus. 

2. Histoxs. — These closely resemble the protamins, differing in 
the complexity of the molecule, which in histons is more like that 
of a pure albumin in a simpler form. The protamins seem to be 
constituents of the more highly developed histons, which yield a 
greater number of amino-acids on hydrolysis. Histons are like 
the albumoses in their reactions, are basic, and most of them con- 
tain iron. Among them is globin of the red blood-corpuscle and 
nucleohiston from the thymus gland of the calf (p. 532). They 
are distinguished by being precipitable with ammonia. 

3. Albumixs. — These dissolve in pure water, coagulate when 
heated, and precipitate from solutions saturated with ammonium 
sulphate. They include serum-albumin of the blood, ovalbumin 
of egg, lactalbumin of milk, and myo-albumin of muscle. 

4. Globulixs. — These do not dissolve in pure water, but are 



528 CYCLIC COMPOUNDS 

soluble in a 0.5 to 1 per cent, solution of neutral salts, coagulate by 
heat, precipitate from solutions saturated with magnesium sulphate 
or sodium chlorid, or by addition of an equal volume of saturated 
solution of ammonium sulphate. They include serum-globulin, 
lactoglobulin, myoglobulin and its derivative myosin, fibrinogen 
and its derivative fibrin of clotted blood. 

5. Scleroproteins. — Under this head are grouped the proteins, 
which differ somewhat among themselves and yet are alike in 
resisting the action of the agents which dissolve the other proteins 
referred to above. They are the horny, elastic, tough, gelatinous 
substances found in bone, cartilage, connective tissue, epidermis, 
hair, etc. The list given below contains the important members 
of skeletal origin. 

Keratins are characteristic of the skin, hair, and nails. They 
are rich in loosely combined sulphur, which appears to take the 
place of oxygen in a simple protein, and which forms a black 
sulphid with lead hair-dyes. They are not affected by gastric juice 
or trypsin, but dissolve in warm caustic alkalis. They dissolve in 
water heated under pressure to i5o°-2oo° C. (302°-392° F.), 
but do not gelatinize. They respond to the xanthoproteic and 
Millon's reactions. 

Elastins are found in the yellow elastic tissue of ligaments. 
They are digested by the gastric juice and by trypsin; are insol- 
uble in water unless heated under pressure; are soluble in nitric 
acid and in boiling alkalis. 

Collagens may be considered under two varieties: ossein of bone 
and chondrogen of cartilage and tendons. Dry collagen is yellow, 
hard, and insoluble. By boiling in water or dilute acid it swells 
up and forms gelatin or glue, which makes a clear solution, turn- 
ing to jelly when cooled. Gelatin is soluble in gastric juice and 
trypsin, but is not coagulated by heat nor precipitated by acetic 
acid. It is precipitated by hydrochloric acid, phosphotungstic 
acid, and bromin water. Collagen unites with tannic acid in the 
form of a tough and durable substance, common leather. Gelatin 
responds to the biuret and xanthoproteic reactions, but not to 
Millon's. 

6. Phospho proteins. — Vitellin of egg and caseinogen with its 
derivative casein are members of this group. Caseinogen, the 
principal protein of milk, by the action of rennin, yields the casein 
of cheese. Boiling does not coagulate it, but causes it to split off 
some sulphur and lessens its digestibility. It contains phosphorus, 
but no carbohydrate group, the latter being supplied to the suckling 
by the lactose of the milk. Casein contains phosphorus in direct 
combination with the protein and not in a nucleic acid group, as in 
the nucleoproteins. 



PROTEINS 529 

7. Conjugate Proteins. — This class includes the proteins 
which are capable of being decomposed into a simple protein and 
some other substance of different character. The non-protein sub- 
stances yielded b) r the splitting give the character and name to the 
subclasses in which they are grouped; thus, they are hemoglobins, 
glucoproteins, phosphoglucoproteins, nucleoproteins. 

a. Chromoproteins. — The typic compound is the hemoglobin, 
which gives color to the blood and carries oxygen to the tissues. In 
the corpuscles it exists as an insoluble amorphous combination, 
constituting 40 per cent, of their weight. When free it is readily 
soluble in water, insoluble in alcohol and ether, and crystallizable 
in beautiful red crystals which differ in shape in the hemoglobin 
of different animals. The form of combination found in asphyxia 
is called common or reduced hemoglobin; that in ordinary arterial 
blood, richer in oxygen, is called oxyhemoglobin. Owing to its 
remarkable capacity for absorbing gases in a loose combination 
it is an easy matter to convert one into the other by means of ox- 
idizing and reducing agents. 1 The proportion of the two hemo- 
globins in venous blood is intermediate between that in arterial 
blood and that in the dark blood of asphyxia. The absorption 
power for carbon dioxid, carbon monoxid, hydrogen sulphid, and 
hydrocyanic acid results in combinations which not only poison 
the tissues, but also interfere with the normal absorption powers 
for oxygen. When a solution of hemoglobin is heated to 70 ° C. 
(158 ° F.) or hydrolyzed by acids or alkalis, it splits into the 
simple protein, globin, and a colored derivative containing iron, 
hematin. 

The empiric formula for the hemoglobin of the dog is — 

^758 -^^OS-^ 195 ^218-^ e ^3' 

Hematin, unlike the globin, dissolves in acidified alcohol and 
dries in a blue-black powder which, with hydrochloric acid, forms 
hemin crystals (Plate 4, Fig. 3), a characteristic test. (See Hem- 
aturia.) 

C 32 H 32 N 4 FeO, + HC1 — *■ C 32 H 31 ClN 4 Fe0 3 + H 2 0. 
Hematin. Hemin or chlorhematin. 

It is met with in the blood and in the urine after poisoning from 
hydrogen arsenid. In alkaline solutions its spectrum gives a 
single, poorly defined absorption band extending from C to D 
(Plate 4, f and h). 

1 The dissociation that occurs in the blood under normal conditions is represented 
as a reversible process in this equation: 

Oxyhemoglobin ~^"»» Hemoglobin + Oxygen 

34 



530 CYCLIC COMPOUNDS 

Spectroscopic Tests. — The best method of distinguishing the 
several hemoglobins is by their absorption spectra, shown in 
Plate 4. 

Oxyhemoglobin gives a spectrum which varies with the degree 
of dilution of the arterial blood used for the observation. The 
blood is opaque when observed in a vessel of usual thickness,, but 
when diluted, permits more and more light to pass until the red, 
orange, and green colors appear with a band in the green (Plate 
4, b). Further dilution permits the typic double band to appear 
to the right of the D line (Plate 4, a). This characteristic spec- 
trum is discernible even when the observation is made on a layer, 
1 cm. thick, of a solution 0.01 per cent, in strength. 

A change takes place, to reduced or common hemoglobin, by 
the action of Stokes' reagent (ammoniacal solution of ferrous tar- 
trate) 1 or other reducing agent (Plate 4, c). 

Reduced hemoglobin shows a spectrum with a single broad band 
to the right of the D line (Plate 4, c). Agitated with air, the 
solution absorbs oxygen until all the reduced hemoglobin is con- 
verted to oxyhemoglobin, changing in color from purple to red. 

Methemoglobin is a brownish, soluble substance produced 
when oxygen is united with hemoglobin in a form less readily separ- 
able than in oxyhemoglobin. It occurs in blood that has decom- 
posed or that has been treated with various reagents like amyl 
nitrite or potassium ferrocyanid. In the body it is found in bloody 
transudates and cystic contents; also in the blood of the vessels and 
in the urine in hematuria following poisonous doses of antipyrin, 
phenacetin, potassium chlorate, and amyl nitrite. In neutral 
fluids its spectrum shows a band between C and D like that in 
Plate 4, g, connected by shading with one of the bands of Plate 4, d. 
When in a weak solution faintly alkaline with ammonia, as in stale 
urine, the spectrum is different, the line between C and D moving 
to the right (Plate 4, d). Reducing agents change the spectrum 
of its alkaline solutions to that of reduced hemoglobin (Plate 4, c). 

Hematoporphyrin. — When hematin is treated with sulphuric 
acid that has been saturated with hydrobromic acid, the iron is 
split off, and the remainder, iron-free, is a new dark pigment, 
hematoporphyrin : 

C 32 H 32 N 4 Fe0 4 + 2 HBr + 2H 2 — ^ 2 C 16 H 13 N 2 3 + H 2 + FeBr 2 . 
Hematin. Hematoporphyrin. 

It is the cause of the dark color of the blood in certain diseases, 
in intestinal hemorrhages, and in chronic poisoning from sulphonal 
and from lead. 

1 Stokes' reagent: Mix ferrous sulphate, 3 gm., with 3 gm. of tartaric acid 
dissolved in water, and add water to 100 c.c. Before using, add enough ammonia 
water to dissolve the precipitate and leave an alkaline reaction. 






. 



PLATE 4. 
BLOOD=SPECTRA AND BLOOD-CRYSTALS. 

Fig. 1, a. Normal Solar Spectra, with the various absorp- 
tion-lines marked by letters (A, B, C, D, a, b, a). 
The blood changes the spectrum of the light pass- 
ing through (marked dilution of the blood is neces- 
sary) in such a way that, in accordance with the 
behavior of the hemoglobin present, various por- 
tions of the colored spectrum are obliterated or 
absorbed. There thus appear at various places 
black bands of varying thickness. 

b. Spectrum of blood rich in oxygen (oxyhemoglobin- 
spectrum) (two bands between D and E). 

c. Spectrum of reduced hemoglobin. 

. d. Spectrum of methemoglobin weak solution, faintly 
alkaline with ammonia (accompanying hemoglo- 
binemia, destruction of the red blood-corpuscles 
through poisoning with potassic chlorate, pyrogallol, 
sulfonal, toadstools). 
e. Spectrum of reduced CO-hemoglobin. The reduc- 
tion accompanying carbon-monoxid poisoning is 
unattended with disappearance of the two bands 
between D and E; in contrast with reduced oxy- 
hemoglobin (Fig. c). 
f.-h. Spectra of hematin in acid and alkaline solutions 
and reduced (occurs in urine). 
Fig. 2. Hematoidin Crystals (from old hemorrhagic focus). 
— Partly in rhombic plates, partly in granules. 

Fig. 3. Teichmann's Hemin-crystals. — They serve for the 
demonstration of even slight traces of blood, old or recent. 
They are obtained by adding to the remnant of blood a crystal 
of sodic chlorid and a drop of glacial acetic acid, and effecting 
evaporation by gentle heat. Their recognition is of importance 
from a medico-legal point of view. 

(Jakob.) 



PLATE 4. 



A u B 


C 1 


) J- 




i I' 






II 


! 













1 11 


| | 1 | 



mmm 


in i 


CI 



! 1 


II 111 I 




PROTEINS 531 

Hematoidin is an iron-free, crystalline solution developed from 
old extravasation of blood. It is identical with bilirubin (Plate 4, 
Fig. 2). 

Carbon monoxid hemoglobin is a stable compound formed in 
the blood of persons poisoned from the inhalation of carbon mon- 
oxid or illuminating gas. A molecule of carbon monoxid unites 
with a molecule of hemoglobin in a fixed and definite compound. 
Unlike oxyhemoglobin, it will not give or take oxygen, hence the 
oxygen-carrying function is destroyed if much be inhaled, and 
the victim dies of asphyxia. 

The blood is bright red and shows a spectrum with two bands 
almost identical in position with those of oxyhemoglobin (Plate 
4, e). Stokes' reducing fluid does not change the carbon mon- 
oxid spectrum, and the blood, mixed with an equal volume of 
caustic soda (specific gravity 1.3), yields a bright red mass. The 
mixture of normal blood with the alkaline reagent is dirty 
brown. 

b. Glucoproteins get their name from the fact that on heating 
with dilute mineral acids they yield a simple protein and a substance 
which, like glucose, reduces alkaline cupric solution. They are 
divisible into true mucins, chondroproteins , and mucoids. 

Mucins occur in the secretions of mucous membranes and 
mucous glands; also in connective and epithelial tissues. With 
alkaline water they form slimy solutions which are precipitated 
with acetic acid. They are insoluble in excess of the acid, and 
not coagulated by heat. They are not affected by the gastric 
juice. When hydrolyzed by heating with dilute acid they split 
into acid albuminate and a carbohydrate — mucose. 

Mucoids are glucoproteins found in intestinal mucus, vitreous 
humor, white of egg (ovamucoid), and in the umbilical cord. They 
differ from true mucins in solubility and in not being precipitated 
by acetic acid. 

Chondroproteins, on being hydrolyzed by heating with dilute 
mineral acids, split into a protein called chondroitin, and an ester- 
sulphuric acid in union with a carbohydrate. This ester acid, 
joined with nucleic acid and a protein, constitutes nucleo-albumin, 
a substance precipitated from some samples of urine on the addi- 
tion of acetic acid. 

The principal chondroproteins are the diondro mucoid of car- 
tilage, and amyloid, the peculiar substance deposited in the cap- 
illaries and cells of the kidneys, liver, and spleen as a result of 
wasting diseases, causing amyloid degeneration. Amyloid tissues, 
like starch, turn blue on being treated with sulphuric acid and 
iodin. They color red-brown with iodin alone; bright red with 
eosin; and red with anilin green. Amyloid is insoluble in water, 



532 CYCLIC COMPOUNDS 

amorphous, white, not dissolved in gastric juice, and responds to 
the xanthoproteic, biuret, and Millon's reaction. 

Phosphoglucoproteins are compound proteins rich in phos- 
phorus, which differ from nucleo-albumin and nucleoprotein in 
been hydrolyzed into reducing substances with no xanthin bases 
(see p. 490). 

c. Nucleoproteins are rich in phosphorus, and by hydrolysis 
break up into a protein and a true nuclein. Nuclein splits again 
into a protein and nucleic acid, and the nucleic acid decomposes 
into pyrimidin bases, phosphoric acid, and purin bases. Nucleo- 
histon is a variety present in the thymus gland. Nucleoproteins are 
necessary to cell life in general, especially to the nucleus, and are 
present in all the glandular organs, the spermatozoa, pus-cells, and 
yeast plant. They are not dissolved by gastric juice. In reaction 
they are weak acids, forming soluble salts with bases. They are 
coagulated by heat. They probably constitute the chief mass of 
the protein in cell substance and are most important in relation to 
cell activity. 

Nucleoproteins are distinguished by the products obtained after 
hydrolysis, namely: 

True cell nucleins, which pass from dead cells into the animal 
fluids. They yield proteins and nucleic acid, which latter in turn 
splits into phosphoric acid and purin bases. Gastric digestion 
of nucleoproteins leaves them as insoluble residues. As purin 
bases contribute to the formation of uric acid (p. 490), a regimen 
of food for patients having the uric-acid diathesis reduces the meat 
allowance to a minimum. 

Nucleic acids are set free by the decomposition of nucleins with 
alkalis. They break up into phosphoric acid, pyrimidins, and 
purins. They differ in the bases they contain. All are white, 
amorphous, insoluble in pure water, acid in reactions, forming 
soluble salts with alkalis. They are precipitated by acetic acid and 
are found in the insoluble residue left when a nucleoprotein is 
treated with gastric juice. 

8. Derivatives of Protein. — Of these, the products of protein- 
hydrolysis by enzyms and chemicals are those requiring special 
attention. 

a. Infraproteins are derived from native proteins by digestion 
with alkalis or acids. They do not dissolve in salt solution nor in 
cold water except when a small amount of acid or of alkali is 
present. Heat does not coagulate the solution, but the albuminate 
is precipitated by neutralizing it. Saturation of the solution with, 
sodium chlorid or ammonium sulphate causes precipitation from 
the acid solution, but does not affect the solution in alkali. When 
the alkalis act on native proteins they separate nitrogen and sul- 



PROTEINS 533 

phur from the molecule; hence an alkali albuminate is not convert- 
ible into an acid albuminate, which should contain those elements. 
Alkalis may act on acid albuminates to change them to alkali 
albuminates. An alkali albuminate in water containing calcium 
carbonate dissolves with escape of carbon dioxid. It has acid 
properties which are not shared by acid albuminates. 

During gastric digestion the hydrochloric acid changes myosin 
of muscle tissue to syntonin, a form of acid albuminate. 

Coagulated proteins are produced from native protein by heat, 
acids, alcohol, and other reagents, and by enzyms. Neither the 
process nor the product is understood. Hard-boiled white of egg 
and fibrin are examples. They are insoluble in pure water, in 
dilute acids, alkalis, and solutions of neutral salts. By the enzyms 
of digestion they are changed to peptones and albumoses. Fibrin 
is the white solid protein which appears in clotted blood. A fer- 
ment coagulates the dissolved fibrinogen of the plasma. Similar 
coagulated proteins have been found in the liver and other glands. 

b. Proteoses or Albumoses. — In the digestion of proteins the 
final protein-like substance is called peptone. The process of 
change is one of successive acts of hydrolysis — splitting up the 
molecule. It has many intermediate stages, which are recognized 
by the characteristic proteins derived by the action of the acids 
and enzyms of animal digestion. Syntonin or acid albuminate has 
already been referred to; the others are grouped under the general 
head of proteoses, propeptones, or albumoses. All the proteoses 
are soluble in pure water, non-coagulable by heat, precipitated 
from solution by saturation with ammonium sulphate. 

The proteoses are considered under two classes: primary and 
secondary. The primary includes protoproteoses and hetero proteoses; 
the former in its reactions with neutral salts resemble the native 
albumins, while the latter are like the globulins. The primary 
proteoses are precipitated by 50 per cent, ammonium sulphate in 
acid solution; the secondary require for precipitation a saturated 
solution of ammonium sulphate. Heteroproteose is precipitated 
by saturated neutral sodium chlorid, while protoproteose requires 
saturated acid sodium chlorid. 

The secondary proteoses are derivatives of the primary varieties 
by hydrolytic splitting, and are not precipitated by cupric sulphate. 
Having fewer albumin reactions, they represent further cleavage. 
They are closely related to the peptones. The proteoses differ 
somewhat according to the native protein from which they are 
derived, the parent substances giving the name — as, albumose, glob- 
ulose, vitellose, caseose, etc. 

c. Peptones. — The last of the products of hydrolysis of albumins 
that retain albuminous characteristics are the peptones. They 



534 CYCLIC COMPOUNDS 

closely resemble each other, the difference being unimportant. 
The stages of hydrolysis giving the cleavage products of albu- 
min are shown in this scheme, where all the proteoses (albumoses) 
are seen to end in peptones which are practically of one kind: 

Albumin. 
Primary albumose. 
Hetero-albumose. Protalbumose. Syntonin. 

Secondary albumose. 

Peptones. 
Polypeptids. 
Amino-acids. 

Peptones are very soluble in water, dialyzable, not coagulated by 
heat, not precipitated by ammonium sulphate or by nitric acid, 
with or without neutral salts. In common with other proteins 
they are precipitated by strong alcohol, phosphomolybdic acid, 
mercuric chlorid, and tannin, and give the biuret reaction. 

d. Polypeptids. — Beyond the stage of peptone in the cleavage 
series given above are certain products which consist of two or 
more amino-acids linked together. Some of them give the biuret 
reaction. The majority of the polypeptids are synthetic products 
containing from 2 to 7 different amino-acids. They are optically 
active, like the natural proteins, give the biuret reaction, are pre- 
cipitated by phosphotungstic acid, and are split by trypsin into 
the same hydrolytic products as those yielded by protein. An 
artificial peptid, glyzylalanin, has been made identical with that 
obtained from natural silk fibrin. 

Changes of Proteins in the Body. — As saliva contains no enzym 
capable of causing chemical change in the proteins, they pass to 
the stomach unaltered, except by the disintegrating and dissolving 
effects of mastication. Both the soluble and coagulated proteins 
need to be digested in order to produce absorbable substances. 
These dialyzable products are the result of a series of hydrolytic 
reactions by which the complex protein is broken up into simpler 
compounds. In the stomach by the action of pepsin and acid 
they change into acid albumin, proteoses and peptones, successively 
increasing in solubility and diffusibility with each form. In the 
small intestine the enzym trypsin splits the protein by hydrolysis, 
as does the pepsin, only more rapidly, and the medium is alkaline. 
The remainder in the large intestine undergoes hydrolysis by 
erepsin and putrefaction by bacteria. The products of these 



FERMENTS OR ENZYMS 535 

cleavages of the protein molecule are, successively: proteoses, pep- 
tones, amino-acids, glucosamin, hexon bases, cystin, indol, skatol, 
phenol, and paracresol. The amino-acids and hexon bases, after 
absorption, are synthesized to make the protein tissue materials. 
The four last-named products, for the most part, pass out with the 
feces, but to some extent are absorbed into the portal blood. Their 
poisonous properties are destroyed in the liver, where they meet 
potassium sulphate, which unites with them to form the conjugated 
sulphates excreted later by the kidney. As potassium sulpho- 
phenolate and potassium indoxyl sulphate, etc., they are harmless. 
It is probable that the absorbed products split off a carbo- 
hydrate from the glucosamin, which is easily converted to glyco- 
gen, dextrose, or even fat. 

The carbohydrate and fat are held closely to the protoplasm 
of the cells and are used by it as sources of energy. 

The larger proportion of the body proteins is contained in the 
muscles. In them metabolism is continuous, the massive protein 
molecule not breaking down to free nitrogen, carbon dioxid, and 
water, but chiefly into ammonium salts, lactate and carbamate, 
and partly into glycocoll and other amino-acids with creatin, which 
ultimately changes to creatinin and ammonium lactate. All of 
these, on passing through the liver, change to urea, which ultimately 
escapes in the urine (p. 492). 

The sulphur of the proteins is oxidized finally to mineral sul- 
phates, part of which are eliminated by the kidneys as such and 
part joins in the liver to the aromatic radicals, phenol, indol, and 
skatol, as stated above. 

The nucleoproteins of the tissues are much less abundant than 
the muscle proteins. They are found chiefly in the gland cells and 
split into true protein and nucleic acid, which later breaks down 
into phosphoric acid and the purin bases. The latter ultimately 
in the liver oxidize to the uric acid of the urine. Thus, the metab- 
olism of the tissues produces uric acid as regularly as muscle sub- 
stance forms urea. 

The small amount of hippuric acid found in urine is derived 
partly from food and partly from the oxidation of aromatic groups 
of protein metabolism into benzoic acid. In the kidney the benzoic 
acid is joined with glycocoll to form hippuric acid, and is then 
excreted. 

FERMENTS OR ENZYMS 

Fermentation is the transformation of an organic substance 
produced by an enzym acting by catalysis (p. 395). The enzym 
is secreted in the living body by cell action or is produced by the 
processes of nutrition of low organisms. At one time these organ- 



536 CYCLIC COMPOUNDS 

isms — bacteria, molds, etc. — were called the true ferments, and 
their soluble enzyms called jalse ferments; but it is now established 
that the living molds act because they contain the ferment, and 
the true agent in every case is the soluble enzym. Moreover, this 
product of cell life can manifest its special activity after the death 
of the parent call. As yet the enzyms have not been isolated in 
a chemically pure form. They are commonly regarded as albu- 
minous, but this may be only an appearance due to the adherent 
particles of protein matter. They are soluble in water, yet are 
not diffusible, and are precipitated by ammonium sulphate or 
strong alcohol. It is probable that some of them are colloidal 
combinations of organic substances with metal ions, such as man- 
ganese and iron. 

Enzyms are very susceptible to certain external influences. Al- 
though they resist some protoplasmic poisons, such as chloroform, 
thymol, salicylic acid, arsenous acid, boric acid, and glycerin, 
they are paralyzed by mercuric chloridj carbolic acid, and sul- 
phites. Their action is arrested by absence of water, to be re- 
stored when moisture is abundant. As a general rule, the animal 
ferments, when moist, are killed by a temperature of 75 ° C. (167 ° 
F.), and the vegetable ferments by 80 ° C. (176 ° F.). When dry 
they may withstand a temperature of 150 C. (302 ° F.). Very 
low temperature may destroy their action entirely, but this does 
not always occur. They are most active at the temperature of 
the animal body. An enzym selects specifically the substance 
upon which it works. Thus, one decomposes a certain sugar of 
an isomeric group, but does not affect the others, almost identical. 
This enzym must have a stereochemical structure related to the 
stereochemical structure of the sugar as a key fits into a lock. 

The functions of the enzyms are specific and well understood. 
In most cases they hydrolyze, i. e., cause a reaction with water, ending 
in cleavage of the substance upon which they act. In other cases 
they are concerned with the oxidations of the tissues. In some 
way they communicate such disturbances to the complex albumin- 
ous or polysaccharid molecules as to lead to simpler and more 
stable combinations. In this they act like the catalyzing colloidal 
solutions of metals, which accelerate certain reactions (p. 87). In 
both cases the amount of transformation is out of proportion to 
the quantity of the agent, and the agent is not used up, as it takes 
no part in the reaction. Colloidal platinum breaks up 1,000,000 
times its quantity of hydrogen peroxid and remains as strong as 
ever. It also inverts cane-sugar, like invertase, and acts on certain 
fats like a fat-splitting enzym. The poisons which inhibit the 
ferments, such as mercuric chlorid and hydrocyanic acid, also 
paralyze the catalytic action of colloidal platinum. 



FERMENTS OR ENZYMS 537 

Ferment action is not only one of decomposition, but also may 
at times be one of construction. Maltose is not completely changed 
by its ferment into glucose, but only up to a point of equilibrium. 
Using concentrated solutions of pure glucose, the same ferment 
reverses its action and builds up maltose to the same point of natural 
equilibrium between the fermented substance and its products. 
The fat-splitting lipase causes not only the hydrolysis of ethyl 
butyrate into alcohol and butyric acid, but, with a change in the 
acting masses, also the reverse synthesis of alcohol and acid into 
the ester. Thus the same enzym may split or may build up fats 
according to the concentrations present. Fat is digested by steap- 
sin in the intestine only when the resulting glycerin and fatty acids 
are removed as they are formed. In the fluids of the tissues, on 
the other hand, the glycerin and acids are in excess, the activity of 
the enzym is reversed, and fat is deposited. During starvation the 
lipase acts directly on the fat deposits and the fatty acids and 
glycerin of the cells diffuse into the blood. From this it appears 
that the intracellular enzyms not only break down and clear away 
effete matter, but act synthetically and probably maintain the 
normal equilibrium between the cell contents and the serum of 
blood or lymph (p. 83). 

It is now established that enzyms are omnipresent in the cells 
and take part in almost all chemical changes in the living body. 
The liver-cells alone exhibit such varied catalytic powers that we 
must assume the presence in them of twenty different enzyms. 
Only the principal groups concerned in digestion, nutrition, and 
secretion are referred to in the list on p. 538. 

Nomenclature. — In order to simplify the nomenclature, it is 
proposed to attach the suffix -ase to the stem of the name of the 
substance upon which it acts; thus, saccharase is the specific enzym 
of saccharose. 

Classification. — A good basis for grouping the ferments is 
found in their specific functions and the products of their action. 
Three classes of great interest are those which hydrolyze the food- 
stuffs, proteins, carbohydrates, and fats. In the following arrange- 
ment they are mentioned first: 

Proteases {Proteolytic Enzyms). — Pepsin of the stomach and 
trypsin of the pancreas are digestive ferments which break up the 
complex non-dialyzable protein molecules into proteoses and pep- 
tones. Erepsin, which is found in the intestinal mucus, hydro- 
lyzes proteoses to amino-acids. The power of self-digestion, 
shown by the antiseptic tissues after death, is due to autolytic pro- 
teases (pp. 523 and 545). 

Amylases (Amylolytic Enzyms). — Ptyalin of the saliva, the 
diastases of the pancreas, of the liver, and of vegetables, hydro- 



538 CYCLIC COMPOUNDS 

lyze the starch molecule and split it into a disaccharid maltose, 
with dextrin as an intermediate product (pp. 543 and 556). 

Invertases (Inverting Enzyms) . — In the saliva, in the pancreatic, 
and in enteric juices ferments are found which invert the disacch- 
arids to monosaccharids, saccharase acting on cane-sugar, maltase 
on maltose, lactase on lactose (p. 557). 

Lipases (Lipolytic Enzyms). — The hydrolysis of fats to fatty 
acids and glycerin is accomplished by the steapsin of the pancreas 
and also by lipases in the gastric juice and the tissues generally 
as intracellular enzyms (pp. 545 and 557). 

Urases are enzyms that hydrolyze urea into ammonium car- 
bonate. They are secreted by various bacteria that excite am- 
moniacal fermentation in stale urine (p. 585). 

Nucleases are enzyms in the tissues which split nucleic acid 
into phosphoric acid and the purin bases (p. 492). 

Next in point of interest come the ferments, the special action 
of which is to oxidize albuminous substances in the cells. 

Oxidases (Oxidizing Enzyms). — The oxygen carriers are di- 
vided into three groups, two of which, oxygenases and perox- 
idases, yield oxygen to other substances and then immediately 
reoxidize themselves. The third, catalases, cannot reoxidize 
themselves from the air. 

Oxygenases turn tincture guaiac blue by direct transference of 
the molecular oxygen of the air. 

Peroxidases are bodies which contain manganese, aluminium, 
iron, and possibly copper. They are quite stable and do not ox- 
idize directly, but only in the presence of peroxids. Only on the 
addition of hydrogen peroxid will they turn guaiac blue. 

Catalases are the agents in protoplasm which decompose hy- 
drogen peroxid so that the peroxidases can utilize the liberated 
oxygen. They do not turn guaiac blue directly nor in the pres- 
ence of hydrogen peroxid. 

Guaiac Test for Oxidases. — Make a fresh tincture of guaiac by 
boiling pieces of guaiac with alcohol in a test-tube. When a deep 
yellow color is developed, filter and add a few drops of the filtrate 
to water until a milky emulsion is formed. A slice of raw potato 
indicates the presence of oxygenases by turning the emulsion blue. 
If, instead of potato, some blood or raw meat, minced, containing 
peroxidases be immersed in the emulsion, there is no change until 
hydrogen peroxid is added, when the blue reaction appears. If 
bubbles of free oxygen form on the tissue after the peroxid is added, 
catalases are present. 

Coagulases (Clotting Enzyms). — These comprise thrombose, 
which coagulates the fibrin of the blood; and rennet, which curdles 
milk. As calcium salts are necessary for their action, it is probable 



ENERGY OF FOODS 539 

that the clot is a calcium compound of fibrin or casein (pp. 545 and 

562). 

Having a very different chemical effect are: 

Reductases (reducing enzyms), such as the one that reduces 
sulphur to hydrogen sulphid. 

Glue osid- splitting enzyms play an important part in certain 
medicinal plants. Mention has been made (pp. 443 and 464) 
of the action of emulsin or synaptase upon amygdalin. Another 
example is the action of myrosin upon the sinigrin (myronic acid) 
of mustard seed, which develops allyl mustard oil. 

On the other hand, synthesis of amygdalin can be brought about 
by the enzym maltase acting upon mandelic nitrile and glucose: 

C«H 17 NO e + C 6 H 13 6 = C 20 H 27 NO n + H 2 0. 

Mandelic nitrile. Amygdalin. 

The alcohol and acid-forming fermentations are fully described in 
other places (p. 444). 

Autolytic enzyms are found in the tissues generally. They are 
supposed to split proteins into nitrogenous bases, such as the purins 
and amino-bodies. Guanase of the thymus gland, adrenals, and 
pancreas converts guanin to xanthin. Adenase of the spleen, liver, 
and pancreas converts adenin to hypoxanthin. The breaking-up 
process continues in the liver and spleen until uric acid is produced, 
and this itself is destroyed by enzyms. These uricolytic enzyms 
have been found in the liver, kidney, muscles, and bone-marrow. 
The uric acid' is split by them to glycocoll, allantoin, and oxalic acid. 

Normal milk has enzyms favorable to the digestion of the milk 
(P- 5 6 7)- 



ENERGY OF FOODS 

In the preceding pages we have studied the properties of foods 
and of the proximate principles of the human body, and stated 
briefly the chemical changes they undergo while subject to the proc- 
esses of life. These changes in the principles of the organism are 
incessant. It is necessary to life that the elementary atoms should 
not remain in stable groups, but forever be moving from one 
unstable organic form to another. In another place (p. 109) it has 
been stated that matter is indestructible, and that the forces which 
move matter are phases of one energy, the total of which is not 
diminished or increased. The union of carbon and oxygen converts 
the potential energy of the two separate elements into the measurable 



540 FOODS AND DIGESTION 

kinetic energy of heat. Energy under appropriate conditions takes 
the different forms of light, electricity, magnetism, mechanical 
motion, or, in the animal body, the collection of forces that con- 
stitutes life. 

From the energies of the sunbeam the leaf of the plant derives 
power to decompose carbon dioxid. From the earth, by its rootlets, 
the plant obtains water, nitrates, and other mineral salts. The 
sunbeams supply energy for the synthesis of these simple sub- 
stances into the complex molecules of starch, sugar, glutin, oils, 
etc. These food principles are stores of potential energy for the 
animal, which reverses the chemical processes, liberating the energy 
in active forms as the proteins and carbohydrates break up into 
urea, carbon dioxid, and water. These animal excreta in turn be- 
come food for plants (p. 104). The organic food materials which 
animals take from plants are not assimilable in their original state. 
After they are eaten they must be altered chemically before they 
are suitable for absorption. Digestion is the sum of the chemical 
processes preliminary to absorption. Metabolism includes the 
processes of nutrition and secretion taking place after absorption 
in the fluids and cells of the tissues. They are partly constructive 
(anabolic) of digested products into protoplasm, and partly destruc- 
tive (katabolic) of protoplasm into excrementitious substances. 
Metabolism may be regarded as the efforts of the enzyms to main- 
tain an equilibrium in cell substance which must be continuously 
readjusted because of the loss of balance due to oxidation or other 
changes in the components of cells. 

Foods. — The substances actually needed by the body to maintain 
physical and mental strength, health, weight, endurance, and re- 
sistance to disease are called foods. 

These must be supplied not simply in the minimum amount 
and proportion to keep an equilibrium between waste and repair, 
but with an additional allowance to provide against the danger of 
under-nutrition when unusual stress occurs. An undue supply 
above the correct requirements may prove not only wasteful, but 
even injurious, by the unnecessary tax put upon the katabolic proc- 
esses and the eliminating organs. The various kinds of food-stuffs 
used by man have constituents that can be arranged in four groups, 
viz.: (1) Proteins or albuminous substances; (2) carbohydrates 
(sugar, starch, etc.); (3) fats; (4) inorganic salts. 

Proteins or Nitrogenous Foods. — From both vegetable and 
animal sources we obtain albuminous substances essential to life, 
containing, when dry, nitrogen, about 16 per cent. They are 
abundant in bread, cereals, peas, beans, fish, eggs, and meat. The 
two last-named, eggs and lean meat, are almost entirely protein. 
Bread and cereals are composed mostly of the carbohydrate starch, 



ENERGY OF FOODS 541 

but all have some protein. Flour has 13.5 per cent, protein and 
fresh green peas 7 per cent. The destiny of protein is to be oxi- 
dized for the most part to urea, carbon dioxid, and water. Urea 
is not a final oxidation product, and hence contains some energy 
not fully utilized in the body. The food value of proteins is, there- 
fore, not perfectly expressed in terms of complete oxidation, like 
that of the carbohydrates, but in terms of nitrogen content in 
addition to juel value. 

Carbohydrates. — The foods of this class contain no nitrogen, but 
belong to the family of saccharids (p. 434). They are the sugars 
and starches derived mainly from plants, and either eaten pure 
after separation or taken with the other constituents of the vegetable. 
Eaten in the dry state, these foods are almost wholly carbohydrates, 
rice being 79 per cent, starch and 8 per cent, proteins. Allowing 
78 per cent, for water in the raw potato, 18.5 per cent, is starch 
and 2.2 per cent, protein. 

Fats. — Derived from both plants and animals are olive and 
cotton-seed oil, butter, bacon, and tissue fats made up of the non- 
nitrogenous compounds, stearin, palmitin, olein, and other fats. 
Being rich in carbon, they are very combustible, and liberate a 
large amount of heat when oxidized. 

Inorganic Salts. — The mineral phosphates, chlorids, carbonates, 
and sulphates are necessary for the various secretions and pro- 
motion of tissue changes, but in great part they circulate in and 
pass out of the body without much change. 

Energy Value of Food. — Excepting the inorganic salts, all the 
food-stuffs are combustible. By burning them with oxygen in a 
calorimeter the units of heat set free can be determined and used 
as an equivalent of nutritive potency. It has been stated (p. 34) 
that 1 gm. of a carbohydrate yields 4100 small calories or 4.1 Cal. 
(p. 73). The same heat value is shown by 1 gm. of protein. One 
gram of fat gives a much larger amount, viz.: 9300 small calories 
or 9.3 Cal. 

Fats and carbohydrates serve best as sources of ordinary poten- 
tial energy, but to replace the substance of tissue wasted at least an 
equivalent amount of protein is required in the food. The oxi- 
dation products of the fats and carbohydrates are the easily elimi- 
nated water and carbon dioxid. On the other hand, the metabolism 
of nitrogenous substances is attended by the formation of purin 
bases, uric acid, and other compounds intermediate between protein 
and the final excrementitious form, urea. These substances above 
a normal or average mean for the individual are not readily elimi- 
nated, and when retained may be the cause of mischief more or less 
serious. They are especially hurtful when the excretory organs 
such as the kidneys fail to do their share of the work of removing 



542 FOODS AND DIGESTION 

effete matter. It is of prime importance to know, on the one hand, 
how much food is usually consumed to satisfy the natural craving 
in a liberal manner and, on the other hand, how little is actually 
required for the needs of the body under ordinary conditions in 
the service of health, but not of luxury. 

Dietary Standards. — Analysis of the diet of laborers and 
soldiers of different nationalities has shown that the average daily 
consumption provides for a total fuel value of over 3000 Cal. 
The protein average is about 120 gm., containing 19 gm. of nitrogen. 
The American professional man or sedentary person with moderate 
work usually takes 100 gm. of protein with fats and carbohydrates, 
giving energy equivalent to 2700 Cal. The researches of Chittenden 
upon the diet of professors, athletes, and soldiers, when not taxed by 
excessive physical or nervous strains, show conclusively that the 
customary dietaries are in excess of the indispensable minimum 
and, therefore, in the long run might prove objectionable in a case 
of inadequate action of the excretory organs, even if the economic 
aspects be ignored. He found that professional men living regular 
and care-free lives can maintain a state of nitrogen equilibrium 
with a daily diet containing 50 gm. of protein and an additional 
amount of carbohydrate and fat yielding a total energy value of 
about 2000 Cal. Vigorous health of mind and body continued for 
months on this diet, containing one-half the amount of protein and 
two-thirds the calorific power of the standards in use. Athletes 
free from anxieties, but making heavy demands for muscular work, 
were in healthy equilibrium on a daily diet of 56 gm. of protein 
and a total fuel value of about 2500 Cal. The evidence goes to 
show that all the actual needs of the human body under the regular 
conditions of a " simple life" can be served on a diet containing 
much less nitrogen than is customary in the habits and standards 
of mankind. The best dietary is one in which the vegetable foods 
predominate and the heavier meats are taken in moderation. 



DIGESTION 



Mastication. — Digestion begins with the mechanical disin- 
tegration of the food in the mouth by chewing, where at the same 
time it is mixed with saliva. The mass is thus softened, moistened, 
partly dissolved, and made ready for its propulsion into the stom- 
ach. The mixed secretions of the mouth, called saliva, contain 
enzyms which hydrolyze starch and split it into soluble starch, 
dextrin, maltose, and glucose. 



saliva 543 

SALIVA 

This fluid is a mixture of the secretions of the parotid, sub- 
maxillary, sublingual, and buccal glands. It is tasteless, colorless, 
odorless, viscid, and frothy. It is opalescent and turbid from the 
floating particles of food, epithelium, and mucous cells. The flow 
is continuous, but variable, rising in amount by the reflex stimulus 
of chewing and by the smell and sight of food. The average daily 
quantity is from 600 to 1500 c.c. (20-50 fl. oz.). Its reaction is 
faintly alkaline, though sometimes slightly acid after eating; its 
specific gravity, 1002 to 1008; the proportion of dissolved solids, 
5 to 10 parts per thousand. 

In 100 parts there are: water, 99.42; mucin and epithelium, 
0.22; fats, 0.11; albumin and the two enzyms, ptyalin and maltase, 
0.12; salts, 0.13. 

The salts include potassium thiocyanate (sulphocyanid), be- 
sides the alkaline and earthy chlorids, phosphates, and carbonates. 
The digestive power of the saliva is in proportion to the quantity 
of the enzyms. The ptyalin converts cooked starch, through the 
intermediate stages of soluble starch, dextrin, and erythrodextrin, 
into maltose and isomaltose (p. 441): 

io(C 6 H 10 O 5 ) n + 4 (H 2 0) n = 

Starch. Water. 

4(0^0^ + (C 6 H 10 O 5 ) n + (C 6 H 10 O 5 ) n 

Maltose. Achroodextrin. Erythrodextrin. 

The other enzym, maltase, is in smaller quantity, and converts 
maltose into glucose (p. 438). Slightly acid or neutral solutions 
are best suited to the action of these starch-splitting ferments. 
While they have some activity in the weak carbon acids, this power 
is lost when the acidity due to HC1 reaches that of the gastric juice. 
The free acid in the active pyloric end, some time after deglutition, 
destroys the ptyalin, but the salivary fermentation continues first 
for a considerable period in the gastric fundus, which may be neu- 
tral in reaction and relatively quiescent. 

Fermenting Power. — By chewing paraffin, a bit of rubber, or 
glass rod, saliva is made to flow, and collected by spitting into a 
beaker until 50 c.c. are collected. 

Experiment 1. — Having labeled two test-tubes A and B, place 
in A starch paste and saliva. Put in B some saliva, dilute and 
boil it, then add starch solution and stand both in a water-bath 
for ten minutes; meanwhile go on with experiments 5, 6, 7, and 8. 

Experiment 2. — At the end of ten minutes pour half the con- 
tents of A into a test-tube containing a drop of HC1 and a few 
drops of iodin solution. If a purple color develop, then starch 
and dextrin are present; if the color is reddish brown, erythro- 



544 FOODS AND DIGESTION 

dextrin and no longer starch; absence of all color indicates absence 
of both erythrodextrin and starch. 

Experiment 3. — If the remaining half of A is added to boiling 
Fehling's solution and a red precipitate falls, a mixture of maltose 
and glucose is present as the result of fermentation due to ptyalin 
and glucose. 

Experiment 4. — The contents of tube B, when treated by tests 
2 and 3, show a blue color with iodin and no red precipitate with 
Fehling's solution. This denotes that boiling the saliva has de- 
stroyed its power of digestion and the starch is unchanged. 

Chemical Properties. — While waiting for the fermentation 
tests, a further flow of saliva may be caused and the reaction 
taken with litmus paper. 

Experiment 5. — On addition of acetic acid to dilute saliva a 
precipitate shows mucin. 

Experiment 6. — Boiling with strong nitric acid gives a yellow 
color, which deepens if ammonia be added. This denotes a protein. 

Experiment 7. — A drop of nitric acid and silver nitrate shows 
the chlorids by a white precipitate. 

Experiment 8. — Ferric chlorid turns the saliva red from the 
presence of a sulphocyanate. 

GASTRIC CONTENTS 

Gastric Juice. — When food enters the stomach or when the 
gastric mucous membrane is irritated mechanically or chemically, 
there is secreted a fluid called the gastric juice. If free from food 
particles, it is thin, clear, or faintly cloudy, pale yellow, with a 
strongly acid reaction and a specific gravity of 1001 to 1010. In 
a day the amount poured out will vary between 4 and 10 pt., part 
of which is absorbed with the digested product while fresh portions 
are being secreted. By reflex action the production of gastric 
juice is strongly stimulated by the taste of food or bitter substances 
in the mouth. The juice which is secreted by psychic or " appetite' ' 
stimulus is most important, inaugurating gastric digestion, the 
first products of which, when absorbed, in their turn stimulate 
secretion by a reflex circuit including excitable nerve-endings in 
the mucous membrane of the stomach. To excite the secretion of 
this psychic juice, eating must be done with attention and relish. 
Water alone introduced into the stomach will cause some flow, but 
food will increase it greatly. A free secretion does not take place 
until there has been some absorption; hence the advantage of 
having soup as the first course of a meal. When pure and free 
from residues of food, the acid reaction is chiefly, if not wholly, 
due to hydrochloric acid, about 0.2 or 0.3 part per cent. Immedi- 
ately after feeding, especially if the meal be rich in carbohydrates, 
lactic acid appears abundantly. The protein material contained 



GASTRIC CONTENTS 545 

in fresh gastric juice is due to a little mucin and two enzyms, pepsin 
and rennin. 

Average composition of gastric juice. Per cent. 

Water 99-44 

Solids, as tabulated below 0.56 

Organic substances (pepsin and peptones) 0.32 

Free hydrochloric acid 0.25 

Sodium, potassium, and calcium chlorids 0.21 

Calcium, magnesium, and ferric phosphates 0.02 

Pepsin. — A characteristic property of the pepsin is its power of 
converting proteins into dissolved proteoses and peptones in an 
acid, but not in a neutral or alkaline medium. The protein swells 
and clears up before it dissolves. The albumin of hard-boiled egg 
cut into disks 1 mm. thick is not altered by dilute hydrochloric 
acid when immersed in it for several hours at the temperature of 
the body. If, however, pepsin has been present, the edges become 
clear, transparent, and swollen, and the albumin dissolves. On 
the other hand, pepsin alone has no action on proteins, the acid, 
too, being essential (see p. 554). 

Pepsinum, U. S. P., is the enzym as obtained from the glandular 
layer of the fresh stomach of the hog. It occurs in yellowish white 
scales or powder, having a slightly acid taste. It is soluble in 50 
parts of water; more -soluble in water acidulated with hydrochloric 
acid. If that acid is present in greater strength than 0.5 per cent., 
the proteolytic activity is checked and destroyed. It is incom- 
patible with pancreatin, destroying it if the mixture be acid; if the 
solution be neutral or alkaline, the pancreatin destroys the pepsin. 

Rennin, or chymosin, is the enzym which is characterized by 
coagulating the casein of milk. It may be absent in carcinoma, 
chronic catarrh, and atrophy of the membrane of the stomach. 

Chyme is the pulpy mass into which the food is converted in 
the stomach by the action of the gastric juice and saliva. It is 
acid in reaction and contains the transformation products of di- 
gestion of carbohydrates and proteins, mixed with much-changed 
but undigested matter which remains to be digested in the intes- 
tines. The albuminous foods are prepared in the stomach for 
the real digestive process of the intestines. 

A swollen and slippery change marks partial digestion of meat, 
muscle, and cartilage. The combination of pepsin and rennin 
curdles milk either in large lumps of cheese or smaller flocculi 
distributed through the mass. Bread is pulpified, though other 
vegetable foods, such as potatoes, may be found in distinct morsels. 
Part of the starch taken is converted into dextrin and sugar while 
digesting in the quiet fundus. 

It is probable that the fundus secretes a lipase capable of 
splitting emulsified fat. 
35 



546 FOODS AND DIGESTION 

CLINICAL EXAMINATION 

The scope of this section does not include all the physiologic 
and pathologic relations of the stomach contents, but only such 
as have clinical value. The range of the casual examination may 
be summarized in the following procedures, which are enlarged 
upon later on: 

Filter the gastric contents and use the nitrate. 

(4). Test acidity with litmus paper; it may be normal, super- 
acid, subacid, anacid. 

(B) Find the acid when not combined. For free acid use 
Congo red, or tropeolin oo. To tell the kind of acid: For hy- 
drochloric acid use Topfer's reagent, which shows 0.02 per 1000; 
or Gunzburg's reagent, which is delicate for 0.05 per 1000; or 
Boas' reagent, which has the same delicacy as Gunzburg's (p. 549). 

For lactic acid use Uffelmann's reagent, which is delicate for 
0.1 per 1000 (p. 552). 

(C) Determine total acidity: Titrate 10 c.c. of filtrate to which 
has been added phenolphthalein (1 per cent, alcoholic solution), 4 
drops, with a decinormal solution of caustic soda (4 gm. to 1 L.) — 

1 c.c. of this solution = 0.003646 gm. of HC1 or 0.009 g m - °f lactic 
acid. 

Hydrochloric acid is normal at end of first hour in parts 1.5 to 

2 per 1000 (0.15 to 0.2 per cent.); or at end of third or fourth hour 
in parts 2.3 to 3 per 1000 (0.23 to 0.3 per cent.). 

Gross inspection of vomited matters or stomach contents con- 
sists in noting the presence or absence of — (1) food particles and 
whether fresh or old; also the progress of digestion. (2) Blood, 
whether bright or coffee-ground color. (3) Mucus. (4) Odor. (5) 
Apparent amount of gastric juice, keeping in mind that after diges- 
tion is complete the secretion of gastric juice should cease. Continu- 
ous secretion is abnormal and is known as parasecretion (Ewald). 

Microscopic Examination.— Here are to be looked for food 
fragments, starch granules, plant cells, muscle-fibers, connective 
tissues, epithelial cells from mouth and esophagus, cylindric cells 
from the stomach, leukocytes, red blood-cells, pus-cells, parasites, 
and low organisms, as yeast cells, mold fungi, sarcinae, bacteria. 

Gastric Acids. — In the first stage of digestion there may be a 
predominance of lactic acid developed in the fermentation of the 
carbohydrates by the Bacterium lactis; in the second stage both 
lactic and hydrochloric acids occur; in the third stage hydrochloric 
acid has checked the formation of lactic acid, and the acid reaction 
now is due almost exclusively to hydrochloric acid. Decomposition 
of the stomach contents may be prevented for some time by the 
antifermentative action of the hydrochloric acid. If the acid be 
neutralized, the chyme ferments produce lactic, acetic, and butyric 



GASTRIC CONTENTS 547 

acids. To various disease germs hydrochloric acid is an antiseptic 
when present in normal proportions, killing the cholera germ and 
the micrococci of pus. It is one of our chemical defenses against 
disease, but it does not, however, destroy the bacillus of tuberculosis 
nor that of anthrax. It has another action in promoting the sol- 
ution of the calcium and magnesium salts which are required for 
the growth of bone. 

The quantity of hydrochloric acid bears an important relation 
to certain pathologic states, and must be determined so as to aid in 
diagnosis. When there is an excess, the symptom is called hyper- 
chlorhydria; when it is deficient, hypochlorhydria; when absent, 
achlorhydria, and when normal, euchlorhydria. 

It is not only necessary to ascertain the degree of acidity, but 
also the nature of the acid or acids occurring. This may be done 
by coloring substances which give characteristic reactions with 
hydrochloric acid in very minute quantities, but not with lactic 
acid or any organic acid in any degree of concentration found in 
the stomach. It is conceded that these reactions are not suffi- 
ciently distinctive for exact studies, but for comparative studies 
and clinical purposes they are accurate enough, and serve the 
purposes better than more exacting, as well as more difficult, 
methods. To simplify the study and provide a definite point in 
digestion for comparison of data, it is customary to limit the in- 
quiry to the contents of the stomach one hour after a very simple 
meal. At this time the greater part has not passed through the 
pylorus, the secretion of hydrochloric acid has about reached its 
height, and only a trace of lactic acid has been left unabsorbed. 
All the components of an ordinary mixed meal in an easily di- 
gestible form are represented in the test-break) 'ast of Ewald. 

The test=meal is given in the morning as a breakfast. It 
may be given at another time, provided the stomach is empty or 
has been washed out as a preliminary measure. It consists of 
an ordinary roll of dry bread, weighing about 35 gm. (9 dr.), and 
300 c.c. or about 10 fl. oz. of hot water or weak tea, taken with- 
out cream or sugar. In one hour this will be liquefied, and 1 or 
2 fl. oz. (30-60 c.c.) can be easily expressed through a tube. 

The stomach-tube offering the most advantages is a flexible one 
of soft rubber, smooth on the surface and also at the round open- 
ing near the end that enters the stomach. It should be long 
enough to enter the stomach and leave enough tubing outside the 
mouth to reach a receptacle. This outer end may have a funnel 
attachment or an elastic bulb to start the flow of the gastric contents 
until the tube is full enough for siphon action. In an emergency a 
Davidson syringe or a Politzer bag will serve to start the flow. 

The patient sits erect in a chair or on the edge of a bed, with 



548 FOODS AND DIGESTION 

the receptacle near by. The tube, wet in hot water, is passed back 
to the throat and the patient makes an effort at swallowing. Assist- 
ing deglutition, it readily passes into the stomach. Evacuation 
may occur at once, without effort, simply by depressing the ex- 
ternal end of the tube so as to make a siphon. Pressure over the 
abdomen, in the recumbent posture, while the patient coughs or 
bears down, is of material help. When 10 fl. oz. (300 c.c.) of 
water or tea have been given, about ij fl. oz. (45 c.c.) of fluid 
should be obtained by the tube. Filtration yields a clear solution 
for the application of the tests. Should there be much gagging 
from nervousness or pharyngeal irritability, a spray of cocain (4 
per cent.) will prepare the way for the tube. 

Dangers to be Avoided. — Ordinarily, the use of the stomach- 
tube is an easy and safe procedure, but it is contraindicated in acute 
fevers, emphysema with bronchitis, organic heart disease, aortic 
aneurysm, the hemorrhagic diathesis, corrosive poisoning threat- 
ening perforation, and soft carcinoma of the stomach. 

The specimen from the test-meal, when examined by the naked 
eye, need not be searched for all of the numerous objects referred 
to above. If the contents be normal, they will be composed of 
about 40 c.c. of a whitish fluid, some mucus, and a sediment of 
bread debris. After filtration the fluid should contain hydrochloric 
acid, pepsin, rennin, peptone, and mineral salts. 

The chemical examination should begin by the use of litmus 
paper to determine the reaction. Normally, blue litmus will be 
reddened; if it be unaffected, then there is a condition known as 
Anacidity (Plate 5, Fig. 1). 

The next step should be to determine if the acidity be due to 
free acid, to acid salts, or acid proteins. Litmus paper does not 
discriminate these. A very convenient test is made with the anilin 
colors, Congo red or tropeolin 00 (dimethyl orange), both of which 
react to minute quantities of free hydrochloric acid, but are un- 
affected by acid salts or by the organic acids in the amounts present 
after the test-meal. A positive reaction with either serves for 
ordinary purposes. 

Congo-red Test. — Upon Congo-red paper place a drop of the 
gastric contents. A deep blue spot appears if free hydrochloric 
acid be present — as much as 0.005 per cent, (the normal amount 
is 0.25 per cent.). A violet spot or a blue ring only around the 
wet place may be produced by any free acid, either a trace of 
hydrochloric acid or some organic acid — lactic, butyric, or acetic 
(Plate 5, Fig. 2). 

Tropeolin {Dimethyl-orange) Test. — The test is made with sat- 
urated alcoholic solution of pure tropeolin (00). With this solu- 
tion wet some white filtering-paper and then let it dry. Touch 




>J0^ TV 






. 



■i 



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PLATE 5. 

THE MOST IMPORTANT COLOR=REACTIONS OF THE 
GASTRIC JUICE. 

Fig. 1, a and b. When the gastric juice reddens blue litmus- 
paper (b) — that is, exhibits an acid reaction — it may contain: 
free hydrochloric acid, lactic acid, and other organic acids, acid 
salts. 

Fig. 2, a and b. If red Congo-paper is stained bluish-black (b) 
by the gastric juice, only free hydrochloric acid or lactic acid is 
present. 

Fig. 3, a and b. If upon evaporation of the gastric juice in a 
porcelain dish, to which a few drops of phloroglucin-vanillin solu- 
tion have been added, a distinct red ring appears, free hydro- 
chloric acid is present ; if the residue remains yellow, no free 
hydrochloric acid is present (anacidity). 

Fig. 4, a and b. If the gastric juice contains hydrochloric 
acid, the violet color of a dilute methyl-violet solution is converted 
into blue (b). (This test is not absolutely reliable.) 

Fig. 5, a and b. If the gastric juice contains lactic acid, it 
will change the violet color of Uffelmann's reagent (1% solution 
of carbolic acid, with 2 drops of iron chlorid) into a distinct 
yellow (b). This test is more reliable if performed with an 
ethereal extract of the gastric juice (lactic acid being soluble in 
ether). 

(Jakob.) 



PLATE 5. 




4 I) 






GASTRIC CONTENTS 549 

the prepared paper with a drop of the gastric contents. When 
hydrochloric acid is present to 0.02 per cent., a dark reddish 
brown spot appears, which changes to lilac or bluish if gently 
heated on a watch-glass. The organic acids as found in the gas- 
tric contents do not have any effect. In larger amounts they make 
a faint brown stain which does not show a lilac color when heated. 

The Liquid Method of performing this test is to put 2 or 3 drops 
of gastric fluid in a porcelain dish, spread them, and evaporate 
almost to dryness. Touch this residue with a drop of tropeolin 
solution and gently warm. A bluish spot indicates free hydro- 
chloric acid — at least 0.02 per cent. No organic acid gives the blue 
color. 

The most delicate tests for distinguishing hydrochloric acid 
are Topjer's dimethylamido-azobenzol, Giinzburg's phloroglucin- 
vanillin, and Boas' resorcin solutions. They do not respond to the 
organic acids as found in the stomach. 

Topjer's solution is made by dissolving 0.5 gm. of dimethyl- 
amido-azobenzol in 100 c.c. of alcohol. A drop of the gastric juice, 
even when unfiltered, will turn a drop of this yellow solution to a 
cherry-red color. Organic acids affect it only when present to 0.5 
per cent., which is more than is ever found in the gastric contents 
after a test-meal (Plate 6, C, C). 

Giinzburg's Test (Phloroglucin-vanillin). — Use the reagent fresh, 
though it will last for a short while when kept in dark bottles. 
Take of — 

Phloroglucin 2 parts (30 gr.) ; 

Vanillin 1 part (15 gr.); 

Absolute alcohol 30 parts bv weight (1 fl. oz.). 

Or— 

Alcohol, 80 per cent 100 parts by measure (3 fl. oz.). 

M. — Make a clear, pale yellow fluid. 

Boas 1 resorcin solution is a reagent of equal delicacy, has greater 
stability, and is cheaper than Giinzburg's. Take of — 

Resorcin, pure 5 gm. ; 

White sugar 3 gm.; 

Dilute alcohol 100 c.c. 

Method for Gunzburg's or Boas' Tests. — About 5 drops of the 
test solution and three of the gastric contents, either filtered or 
unfiltered, are mixed on a porcelain dish. Heat the dish cautiously 
over a small flame. If free hydrochloric acid be present to 0.005 
per cent., a bright red ring will form at the margin as the mixture 
dries. The heat should not be above no° C. (262 ° F.), or char- 
ring will ensue (Plate 5, Fig. 3). 

Import in Diagnosis. — The regular and complete absence of free 
hvdrochloric acid in the contents taken one hour after the test- 



55o 



FOODS AND DIGESTION 



breakfast is an indication of well-defined structural changes in the 
glandular apparatus, and should lead us to suspect atrophy or 
amyloid degeneration, or the dilation which accompanies gastric 
carcinoma and chronic catarrh. 

A striking reduction of gastric acidity occurs in cancer patients 
even when the cancer is not gastric, but located in other parts of the 
body, free acid being absent in two-thirds of all cases of cancer and 
much reduced in the remaining one-third. In the cancerous con- 
dition the alkalinity of the blood plasma is increased and therefore 
there are fewer hydrogen ions than normal for the gastric cells to 
secrete in the form of free hydrochloric acid. 

If the absence be not regular or persistent, there is a possibility 
that the deficiency is due to nervous influences, such as cause 
atonic dyspepsia. The term hyperchlorhydria is associated with 
the not uncommon condition in which the acid is secreted in excess. 
For the gastric juice to contain more than 0.3 per cent, is in itself 
pathologic, retarding the action of ptyalin on starch. It causes 
various symptoms, such as loss of weight and strength, attended by 
epigastric pain relieved by food, which holds the acid in check for 
a while. 



ESTIMATION OF TOTAL ACIDITY, ACID PROTEINS, FREE HC1, AND 
ORGANIC ACIDS 

The procedure generally adopted is acidi?netry, operating with 
the same standard alkali solution upon the acid gastric contents 
in three different dishes, each with a different indicator, to make 
three different reports: 

Total Acidity. — It has been stated above that hydrochloric 
acid is an antiferment. If detected in the gastric contents one 
hour after a test-breakfast, it may be assumed that there is very 
little organic acid present. After ascertaining the presence of 
hydrochloric acid and absence of lactic acid, to determine the 
total acidity is practically to estimate the amount of hydrochloric 
acid present. A more thorough study is needed when the organic 
acids are detected. 

The reagent required is decinormal sodium hydroxid, each cubic 
centimeter containing 0.004 g m - of NaOH, which neutralizes 
0.00364 gm. of HC1. This solution should be carefully standard- 
ized after the method given on p. 125. In the first dish the indi- 
cator is phenolphthalein, 1 per cent, alcoholic solution, which is 
kept colorless by all free acids and acid proteins, but turns red by 
alkalis (Plate 6, A, A'). 

Method. — To 10 c.c. or 5 c.c. of the filtered gastric fluid in a 
dish or beaker 2 drops of a solution of phenolphthalein are added. 
A buret is charged with the decinormal soda solution, and a few 



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GASTRIC CONTENTS 55 I 

drops at a time are run into the liquid until a deep red color per- 
sists of the same intensity. If 10 c.c. of the gastric contents have 
been used and the amount of hydrochloric acid be normal, it will 
require from 4 to 5 c.c. of the solution to change the color. One 
cubic centimeter will neutralize 0.00364 gm. of HC1; if 3 c.c. have 
been required, then the acidity is calculated thus: 3X0.00364 = 
0.01092 of HC1. To get percentage: 0.01092 X 10 = 0.1092 per 
cent, of HC1. If 5 c.c. of gastric liquid were used, then 0.1092 X 
20 = 0.2184 per cent, of HC1. 

The acidity is expressed for clinical purposes by the number 
of cubic centimeters of decinormal sodium hydroxid which are 
required to neutralize 100 c.c. of the stomach liquid. To get this 
when the operation has been performed on 10 c.c, multiply the 
reading by 10. Acidity of 45 per cent, would then mean that 100 
c.c. of the gastric liquid required 45 c.c. of decinormal sodium 
hydroxid to neutralize it. It would be spoken of as "total acidity, 
45 degrees," in terms of NaOH. The acidity of normal gastric 
contents varies between 40 and 60 degrees. 

Free Acids not Combined with Proteins.— When phenol- 
phthalein is the indicator, the reaction is caused by all free acids 
and by loosely combined acids. If we wish to estimate the free 
acids, but not the acid protein or loosely combined acid, we must 
use another indicator. 

Alizarin (sodium alizarin monosulphonate) in a 1 per cent, 
aqueous solution is acted upon by all acids except the acid proteins. 
The difference between the two numbers, total acidity and acids 
not acid protein, will be the degree or number representing the acid 
protein, or loosely combined acid. 

Procedure. — Add 2 drops of alizarin sulphonate as an indicator 
to 10 c.c. of stomach contents in dish No. 2, and from a buret run 
into it slowly the decinormal sodium hydroxid until a pure violet 
color appears untinted by red. The combined acid does not figure 
in the color changes of this dye 1 (Plate 6, B, B'). 

Acid Protein. — If 2 c.c. of soda solution were required to reach 
the clear violet in the last titration and 3 c.c. were required for 
total acidity, then 3 — 2 = 1 c.c, required for loosely combined acid; 
1 c.c. X 10 =10 c.c, representing degrees of combined acid in 100 
of gastric contents. 

1 Topfer recommends the following preliminary steps to familiarize the eye with 
the color required in the reaction with alizarin sulphonate: 

(a) To 5 c.c. of distilled water add a few drops of alizarin solution. A clear 
yellow color results. This varies somewhat, at times a clear red color resulting. 

(b) To 5 c.c. of a 1 per cent, solution of disodium phosphate add a few drops of 
the alizarin solution. A reddish color with a tinge of violet results. 

(c) To 5 c.c. of a 1 per cent, solution of sodium carbonate add a few drops of 
alizarin solution. A clear violet tint — the reaction to be recognized in the test — 
results. 



552 



FOODS AND DIGESTION 



Free Hydrochloric Acid.— As alizarin indicates all the free 
acids, to ascertain the amount of free HC1, as distinguished from 
the organic acids, another indicator must be used which is affected 
by the hydrochloric acid only. This is the valuable property of 
Topjer's reagent, dimethylamido-azobenzol, in 0.5 per cent, 
alcoholic solution. 

Method. — Having filled the buret with decinormal sodium hy- 
droxid, place in dish No. 3 10 c.c. of gastric contents and 3 drops 
of Topfer's indicator, which is yellow. If it turn red, then HC1 
is present, and we must run in the sodium hydroxid slowly until 
the yellow color is restored. If this be done in the proportion of 
1 c.c. for the 10 c.c. of gastric contents used, then for 100 it would 
be 1 X 10= 10 c.c. of decinormal sodium hydroxid to neutralize the 
free HC1 in 100 c.c. of gastric contents, or 10 degrees. To calcu- 
late percentage in weight of HC1: 10X0.00365 = 0.0365 gm. in 
100 c.c. of gastric contents (Plate 6, C, C). 

Organic acids and acid salts are estimated by subtracting the 
degrees of jree HCl from all acids except acid proteins. In the case 
above given the calculation would be 20 degrees less 10 degrees = 10 
degrees for organic acids and acid salts. 

Detection of Lactic, Acetic, and Butyric Acids.— Lactic 
Acid {Kelling's Test). — To 5 c.c. of gastric contents add 50 to 100 
c.c. of water, so that the fluid shall not be yellow. Treat with 2 
drops of a 5 per cent, aqueous solution of ferric chlorid and hold 
to the light. A distinct greenish yellow color is evidence of lactic 
acid having formed ferric lactate. The presence of a small amount 
of hydrochloric acid has no influence on this reaction, which is due 
to the organic salt being undissociated. 

It is not interfered with by the organic substances of the gastric 
contents, which may make Uffelmann's test useless. 

Carboloferric or Uffelmann's Test. — Prepare Uffelmann's re- 
agent freshly by mixing 1 drop of a dilute solution of ferric chlorid 
(U. S. P.) with 2\ fl. dr. (10 c.c.) of a 4 per cent, solution of car- 
bolic acid and 5 fl. dr. (20 c.c.) of water. When first made, the 
reagent has'an amethystine-blue color (Plate 5, Figs. 5a and 5b'). 

Method. — Equal parts of Uffelmann's reagent and filtered 
gastric contents are mixed, and if more than 0.01 per cent, of 
lactic acid be present, the color changes to canary yellow or 
greenish yellow. The other acids may discharge the blue color, 
but not develop the yellow if the very unusual amount of 0.3 per 
cent, be present. 

Fallacies may occur from the previous color of the gastric fluid 
or the presence of glucose, phosphates, etc., giving color reaction 
that masks the lactic acid. A relatively pure and concentrated 
sample can be obtained by making an ethereal extract. Fill a test- 



GASTRIC CONTENTS 553 

tube three-fourths full with the gastric fluid, add ether, and shake 
vigorously some minutes. Stand aside till the ether separates at 
the top with the lactic acid in it. Then pour off the ether into a 
porcelain dish. Repeat with fresh ether three times. All the ether 
is then evaporated, but not over an open flame. To the residue 
add a few drops of water and then Kelling's ferric chlorid or Uffel- 
mann's carboloferric reagent. If the fluid does not turn yellow, 
there is no lactic acid. 

Acetic and Butyric Acids. — The above ethereal residue reveals 
the presence of any acid by the reaction, and the volatile acetic and 
butyric acids by their odor. 

Butyric Acid. — If a portion of the ethereal extract be diluted and 
a piece of calcium chlorid added, the light butyric acid will float 
like oil globules on the saline solution below. 

Acetic Acid. — A portion of the ethereal extract is carefully 
neutralized by sodium or potassium hydroxid, i drop of solution 
of ferric chlorid is added. Acetic acid forms red ferric acetate, 
which on boiling precipitates as the brownish basic salt. 

Import in Diagnosis. — It has been found that 85 per cent, of 
patients showing a marked amount of lactic acid have malignant 
changes in the wall of the stomach. This lactic acid appears 
simultaneously with the disappearance of the hydrochloric acid 
and is therefore attributed to fermentative changes in the food 
which would have been prevented if the hydrochloric acid had been 
normal in amount (p. 546). 

GASTRIC DIGESTION TESTS 

The power of proteolysis possessed by the gastric contents is 
practically dependent on the presence of pepsin. To test that 
power is to prove that the ferment is active, provided always that 
provision is made for the acidity of the medium. 

Pepsin. — Fibrin is easily digested and is preferred to albumin, 
though it is not so easily obtained. Let fresh blood stand till it 
clots. The clot washed in water at a running tap loses color and 
is called fibrin. It can be kept in glycerin and washed before use. 
Into a test-tube or watch-glass containing 2 dr. or more of filtered 
gastric contents put 2 drops of hydrochloric acid and a piece of 
fibrin. Stand aside for a half hour or more at a temperature of 
40 C. (104 F.). If pepsin be present, the fibrin will be smaller 
by partial solution. For practice the student can make an artificial 
gastric juice by dissolving ij gr. of pepsin in 1 fl. oz. of water and 
adding 5 drops of hydrochloric acid. 

Estimation of Pepsin Strength. — Cut hard-boiled white of egg 
into pieces 2V in - ( J mm.) thick, and punch out disks f in. (10 mm.) 
in diameter. Four test-tubes are labeled by clasping to the necks 



554 FOODS AND DIGESTION 

with rubber bands pieces of paper numbered from i to 4. A 
memorandum must be kept to the effect that there is added: to 
the first 2J fl. dr. (10 c.c.) of the clear filtrate of gastric contents; 
to the second, the clear filtrate + HO, enough to make 0.3 to 0.5 per 
cent, solution, filtrate, 2 J dr. (10 c.c), HC1, 2 drops; to the third, 
the clear filtrate + pepsin in scales, filtrate, 2| dr. (10 c.c), pepsin, 
3 to 7 gr. ; to the fourth, the clear filtrate + HC1 + pepsin as in 2 and 3 
above; place all in a warmer at 40 C. (104 F.) and watch the 
progress of digestion for two hours. 

If pepsin and acid be present in normal amount, the disks will 
all dissolve in one to two hours. If the acid be deficient, then solu- 
tion will not occur in samples 1 and 3, but will occur in 2 and 4. 
If pepsin be deficient, digestion will not occur in 1 and 2 as rapidly 
as in 3 and 4. 

Clinical Import. — Absence of pepsin is rare even in serious dis- 
ease of the stomach. Failure in gastric digestion is seldom due 
to the lack of it. If the flakes of albumin digest without adding 
hydrochloric acid, it does not prove a normal state of things, as 
digestion is possible by the presence of lactic acid alone, though 
the condition is not a healthy one. 

Rennet Ferment, or Rennin.— Take a small amount, 2J dr., 
of neutralized filtrate and add an equal amount of neutralized 
boiled milk. Place in warm chamber at 37.7 ° C. (100 ° F.) for 
ten to fifteen minutes — the milk will curdle. 

Digestion of Albumin.— It is seldom of any value to carry 
the investigation further, but, if desired, tests can be applied to 
determine the progress of the digestion of albumin, as follows: 

(1) Heat the filtrate of stomach contents to boiling: 

(a) Coagulating indicates either albumin or syntonin. 

(b) No coagulation implies that there may be propeptone 
(this is precipitated by cold and redissolved by heat) 
or peptone (heat has absolutely no influence upon it). 

(c) If the filtrate be acid, neutralize a fresh portion and 
heat. A precipitate now indicates syntonin. Filter 
and use filtrate as in No. 3, below. 

(2) Biuret Reaction. — Heat the filtrate with caustic potash, 
and add dilute solution of cupric sulphate, drop by drop, from pipet. 
Note the reaction. 

(a) If an intense purple-red color appear, it indicates pro- 
peptone or peptone. 

(b) If a bluish-violet color appear, there may be albumin or 
syntonin (Plate 8, Fig. 7). 

(3) From c of No. 1, above, take the filtrate and treat with 
acetic acid and potassium ferrocyanid. If there be no precipitate 
and the biuret be positive, then peptone is present. Confirm by 



PANCREATIC JUICE 555 

tannin the salts of heavy metals (mercuric chlorid, potassic iodid, 
etc. J, or phosphotungstic acid, all of which precipitate it. 

Motor Function of the Stomach — Ewalds salol test is used 
to determine the efficiency of the stomach in propelling its contents 
onward to the duodenum. Salol (phenol salicylate i in an hour 
passes into the bowels unafiected by the acid contents of the 
stomach. The alkaline pancreatic fluid splits it into salicylic acid 
and phenol. These are absorbed and appear directly in the urine. 

Method. — Give 10 or 15 gr. of salol in a capsule or coated pill. 
In an hour test the urine for salicylic acid by wetting a piece of 
filter paper with urine and touching the moistened paper with a 
drop of 10 per cent, solution of ferric chlorid. A trace of salicyl- 
uric acid is sufficient to develop a violet ring around the drop. A 
more conclusive result is obtained if the urine is examined after 
thirty hours. The salicylic acid should all have been absorbed 
and eliminated before that time. If the violet reaction should 
appear at this late hour, it is proof of sluggish action of the stomach. 

Diastase. — Take a small quantity of neutralized filtrate and 
add an equal amount of thin starch solution. Place in warmer 
for one or two hours, then add dilute tincture of iodin. This will 
show whether the starch has been converted into sugar or not. 
A blue color means that some of the starch has not been changed. 

For Bile. — Use Gmelin's test, as for bile in urine. 

Absorptive Power of the Stomach.— Give the patient 3 gr. of 
potassium iodid in capsules and test saliva with starch paper after 
acidulating with nitric acid. It should turn blue. 

PANCREATIC JUICE 
The changes in the alimentary bolus, due to insalivation and 
gastric digestion, may be regarded to a large extent as preliminary 
to the digestive processes of the intestines. Those earlier alter- 
ations may be entirely canceled in some animals without material 
differences in the products of digestion. The pancreas is the only 
digestive gland in many animals, and is found in all that have an 
alimentary canal. In the higher vertebrates its destruction means 
death. When the acid contents of the stomach pass into the duode- 
num, a substance is secreted by the duodenal glands called secretin, 
which enters the blood and. passing to the pancreas, starts secre- 
tion there. Reflex excitation of the pancreas, liver, and intestinal 
glands results in a flow of alkaline secretions, which put a stop to 
gastric digestion by destroying the reaction of the chyme and sub- 
stituting one favorable to the activity of the new ferments that are 
destined to carry the alimentary bolus through complex chemical 
changes to the end-products. Beside the internal secretion of the 
pancreas, which is taken up by the blood and serves to regulate the 



55 6 FOODS AND DIGESTION 

sugar production from glycogen in the liver and from protein 
metabolism in the muscles, there is the external digestive fluid elabo- 
rated by the gland cells from the blood and lymph and poured into 
the intestines. The highest rate of flow occurs about three hours 
after eating, but there is another rise two hours later. 

The total amount is about 22 c.c. per kilo of body-weight of 
the animal. In man the daily estimates vary between 150 c.c. and 
500 c.c. (J-i pint). It is a strongly alkaline fluid, clear, colorless, 
odorless, viscid, with a specific gravity of 1008. The secretion in 
the dog contains about 1 per cent, of solids, two-thirds of which is 
composed of albumins, peptones, and ferments, and the other one- 
third of mineral salts and such organic matter as leucin, fat, and 
soaps. The salts are equal in alkalinity to 3 parts per 1000 of 
sodium carbonate. The ferments include at least three enzyms 
that are well defined, and two others about which little is known. 
In the first group are: (1) Amylopsin (pancreatic diastase, 
amylase), starch-splitting. (2) Trypsin (protease), protein-split- 
ting. (3) Steapsin (lipase), fat-splitting. In the little-known 
group is erepsin. 

The relative amounts are the results of a response to the reflex 
stimulus of food. A diet rich in starches causes a rise in the pro- 
portion of amylopsin; one rich in fats, an increase in steapsin. 

Amylopsin is an amylase acting like the ptyalin, though with 
greater energy. All starchy food that passes the stomach unchanged 
is at once converted by this enzym into dextrin and maltose. 

Trypsin is a protease formed from the zymogen secreted by the 
gland cells by the action of a constituent of the intestinal juice 
called enter okinase. It is soluble in water, but not in alcohol. 
When acidulated and boiled, trypsin loses its enzymic power and 
breaks up into an albuminous coagulum and a peptone. Its 
best temperature for work is 40 C.(io4° F.). Traces of free 
mineral acid inhibit its action. In alkaline solution it dissolves its 
proteins, fibrin, albumin, globulin, and gelatin much better than 
the pepsin of the gastric juice, and breaks them up more com- 
pletely. When the alkali albumin changes to the dissolved albu- 
moses, these change, first, to peptones, and later, by the aid of 
another enzym, erepsin, to the amino-acids (leucin, tyrosin, aspartic 
acid, the sulphur compound, cystin, etc.), and the hexon bases 
(lysin, arginin, and histidin). At one of the intermediate stages, 
after the formation of albumose, tryptophan is produced. This is 
skatol-amino-acetic acid. It is regarded as the mother-substance 
of the aromatic products indol and skatol. Its presence is shown 
by the Adamkiewicz reaction (p. 500) and by the violet color pro- 
duced when the protein mixture is acidified with acetic acid and 
treated with two and a half times its volume of bromin-water. 






PANCREATIC JUICE 557 

Steapsin has the property of hydrolyzing and splitting fats into 
glycerin and fatty acids, which change to soap by union with the 
sodium carbonate of the intestinal juices. It is probable that this 
reaction extends to the separation of only a part of the acid, which, 
when saponified, aids in the emulsification and absorption of the 
remainder. Another view is that the fat is all split first and passes 
through the intestinal walls as soap and glycerin, to be built up 
again by cell action to molecular fat on the other side. 

Pancreatinum, U. S. P., is a mixture of the enzyms obtained from 
the fresh pancreas of the hog or ox, and consisting of amylopsin, 
trypsin, and steapsin. It is a cream-colored powder with a faint 
odor and a meat-like taste. It is slowly soluble in water. It is 
rendered inert by more than a trace of mineral acid, by excess of 
alkalis, and by pepsin in solution. 

Fermenting Power.— The most powerful and active fermenta- 
tion of the pancreatic juice is that of conversion of starch into 
maltose. It will act even on unboiled starch. For this test an 
extract may be made by bruising finely minced fresh pancreas with 
glycerin. 

Experiment i. — For the proteolytic fermentation, i per cent, 
solution of sodium carbonate is put in a test-tube and a small 
amount of the pancreatic glycerin is added. Put some of it in 
two test-tubes labeled A and B. To A add a piece of fibrin, and 
after boiling the contents of B put in it a piece of fibrin. Stand 
both in a water-bath for thirty minutes. The fibrin in A will look 
eroded, not swelled as by gastric juice, and when tested by the 
biuret reaction gives the pink color due to peptone. Tube C shows 
no change in the fibrin, indicating that boiling has been fatal to the 
ferment. 

Experiment 2. — Into a test-tube labeled C put starch paste 
and a few drops of the glycerin extract of pancreas, without soda, 
and stand in a water-bath for ten minutes. Take out a few drops 
and test every minute with iodin on a white dish. When the blue 
reaction ceases, test with Fehling's solution; maltose will be shown 
by the red precipitate. 

Experiment 3. — As glycerin does not dissolve steapsin, the pan- 
creatic glycerin will not serve to show the fat-splitting fermentation. 
For this it is best to use a small piece of fresh pancreas or an extract 
made by digesting fresh pancreas, minced, in 4 parts of dilute 
alcohol (1 of alcohol to 4 of water) for five days and then filtering. 
Into a test-tube labeled D put milk and blue litmus with a piece 
of fresh pancreas and stand in a water-bath for thirty minutes. 
The liberation of the fatty acids is shown by the litmus turning red. 

Experiment 4. — If the pancreatic glycerin with sodium carbonate 
solution is shaken with olive oil, an emulsion is formed. 



558 



FOODS AND DIGESTION 



BILE 

The liver secretes bile and pours it continuously into the duode- 
num. The flow increases when food arrives in the duodenum, 
and a second wave rises some hours later, when the digestive prod- 
ucts in the blood stimulate the hepatic cells. It is yellow to green 
in color, alkaline in reaction, and of a specific gravity between ioio 
and 1040. The daily amount in man varies from 500 to 1000 c.c. 
(1-2 pt.). 

In 100 parts about 14 are solids, the rest being water. Of the 
solids, sodium glycocholate and taurocholate make 9 per cent.; 
cholesterin, lecithin, and fat, 1.18; mucinoid material and pigment, 
3; inorganic salts, 0.82. The characteristic salts are sodium com- 
pounds with complex amino-acids — glycocholic and taurocholic. 
Glycocholic acid in the intestine, or by the action of dilute alkalis 
and acids, hydrolyzes and splits into glycin (amino-acetic acid) 
and cholalic acid; thus: 



;H 43 NO ( 



+ 



H 2 



CH, . NH, . COOH + C 24 H 40 O 



2 ' -^ AA 2 
Amino-acetic acid. 



24-^-^40^5 
Cholalic acid. 



Q 

Glycocholic acid. 

Taurocholic acid contains sulphur, and splits after hydrolysis 
into taurin (amino-ethyl-sulphonic acid) and cholalic acid; thus: 



C 26 H 45 N0 7 S + 


H 2 = 


= C 2 H 4 


. NH 2 . 


HSO3 


+ C 24 H 40 O 5 


Taurocholic acid. 






Taurin. 




Cholalic acid. 



Pettenkofer's reaction (p. 560) is obtained by mixing the bile 
salts with cane-sugar and sulphuric acid or with furfurol direct. 
A bright red color appears and later changes to violet. 

Cholesterin is present in the 
nerve tissues, the blood-corpus- 
cles, semen, pus, etc. It is a con- 
stituent of the fat obtained from 
sheep's wool (lanolin). Only 
a small quantity is contained in 
normal bile, but at times it be- 
comes excessive and forms con- 
cretions known as gall-stones. 
Though, like fats, it is soluble 
in ether, it is not a true saponifi- 
able fat, but an alcohol with the 
formula C 27 H 45 OH. Part of the 
wool-fat, adeps lance, U. S. P., 
is cholesterin in combination as 
esters of fatty acids. These esters unite with water to make 
stable emulsions which readily penetrate the skin and carry 




Fig. 84. — a, Cholesterin crystals; b, cystin crys- 
tals (Salinger and Kalteyer). 



INTESTINAL JUICE 559 

medicaments with them. It is colorless, odorless, insoluble in 
water, but soluble in alcohol, which on evaporation leaves it in 
rhombic plates (Fig. 84). 

Gall=Stones are sometimes small and easily passed, though the 
concretion, which in passing the bile-duct gives hepatic colic, is 
ordinarily the size of a small die. The concretion may be as large 
as the gall-bladder. It may be solitary, though they are usually 
multiple. For each flat facet on the surface, one other stone 
must have compressed it. They are usually polyhedral. The 
color varies in different stones — white, yellow, green, red, or black. 
When first voided they are soft and friable, or waxy and soapy. On 
keeping they become hard. The specific gravity varies from 0.8 to 
1. 15. A transverse section shows usually a nucleus of cholesterin 
crystals or pigment surrounded by a zone of radiating structure 
and a cortex that is in concentric layers. The average composition 
is 70 or 80 per cent, cholesterin with pigment, but it may be mainly 
pigment or calcium carbonate. 

The bile pigments are chiefly two, bilirubin and biliverdin. 
They are formed by the breaking up of hemoglobin. The bile 
of carnivora is yellow because bilirubin predominates in it; that 
of herbivora is green from the abundance of biliverdin. The iron- 
free crystals of hematoidin found in old blood-clots are identical 
with bilirubin, and go to prove its derivation from hemoglobin 
(Plate 4, Fig. 2). Bilirubin, C 16 H 14 X 2 03, when oxidized by the 
air or by nitric acid, takes up 1 atom of oxygen and becomes 
biliverdin, C 16 H 18 X 2 4 . In Gmelin's test with nitric acid (p. 560) 
the color changes with the successive degrees of oxidation into 
green, blue, and red pigments, and finally to yellow choletelin, 
C 16 H 18 N 2 6 . By reduction processes in the intestine the bile pig- 
ments yield stercobilin, the pigment of the feces. A portion of 
it is absorbed and finally escapes from the body as the pigment 
urobilin of the urine. 

The role of bile is to a great extent that of an excretion. It 
does not contain enzyms, but acts as an auxiliary to the pancreatic 
juice, neutralizing the acid gastric juice from the stomach, assisting 
in the saponification and absorption of fat and the digestion of 
starch. Its alleged antiseptic powers are considered doubtful. 



INTESTINAL JUICE 

In addition to the pancreatic juice and bile the mixed secre- 
tions of the duodenal (Brunner's) and intestinal (Lieberkuhn's) 
glands have a digestive action on the food after it leaves the 
stomach. This succus entericus appears to have no independent 
effect on native proteins or fats, though it probably has three 



560 FOODS AND DIGESTION 

ferments with the power of "inverting," severally, maltose, cane- 
sugar, and lactose. Together these are called invertin or invertase, 
because their effect on the dextrorotatory disaccharids is to hydro- 
lyze and split them into dextrose and levulose, the latter inverting 
the direction of rotation of the polarized ray (p. 436). 

The trypsinogen of the pancreatic juice has no proteolytic action 
until the trypsin is set free by a ferment of the intestinal juice called 
enterokinase. 

Recent researches appear to demonstrate that the proteoses and 
peptones are not absorbed as such, but are probably first broken up 
to amino-acids and hexon bases in the intestinal wall by another 
ferment called erepsin, and that the various tissue substances are 
formed synthetically from these comparatively simple crystalline 
end-products. The protein molecule may be compared to a barrel 
made of staves of amino-acids. Digestion removes what may be 
called the hoops, and the staves fall apart. The synthetic powers 
of the tissue cells put them together again in such arrangements 
as are fitted to the structure of the tissue. 

Experiment 1 (on Ox-bile). — Having observed its green color, 
bitter taste, odor, and alkaline reaction, take the specific gravity. 
It will be between 1020 and 1030. 

Experiment 2. — Put a small quantity in a test-tube and add 
acetic acid. A string-white precipitate forms of mucin and nucleo- 
albumin. 

Experiment 3 (Pettenkofer's Test jor Bile Salts). — Shake to- 
gether, in a test-tube, bile and a grain of cane-sugar. Pour strong 
sulphuric acid down the side; it makes a purple color in the fluid 
and froth. This denotes the presence of the biliary salts. 

Experiment 4 (Gmelin's Test jor Bile-pigment). — On a white 
plate or capsule smear a layer of bile and let fall upon it a drop 
of yellow nitric acid. A play of colors at the line of junction shows 
the stages of oxidation of bilirubin. 

Experiment 5. — Cholesterin in a concretion supposed to be biliary 
or in a piece of lanolin may be shown by dissolving a portion of the 
concretion in warm alcohol and evaporating a few drops on the 
slide of a microscope. Rhombic plates form (Fig. 84), and if 
heated with a drop of strong sulphuric acid, they turn red at the 
edges. 

Salkowski's Test. — Having dissolved cholesterin in chloroform, 
gently shake with an equal quantity of strong sulphuric acid. A 
blood-red color appears in the solution, while the acid takes a 
green fluorescence. Poured on a white plate, the chloroform gives 
a play of colors, blue, green, and yellow. 



BLOOD 



56l 



BLOOD 

The composition of the blood varies according to the part of the 
system from which it is taken, and according to the conditions of 
food and fasting, exercise and rest, health and disease. It is always 
a red or purple, neutral reacting liquid, with a characteristic odor. 
While circulating in the body, it is shown by the microscope to 
consist of a fluid, plasma, carrying in suspension minute bodies, 
the red and white corpuscles and the platelets. These corpuscles 
constitute 40 per cent, of the volume of the blood and 48 per cent, 
of its weight, and the red ones are sufficient in amount to give to 
the blood its crimson hue (Fig. 85). 




I- 4 






Fig. 85. — Cells of blood: a, Colored blood-corpuscles seen on the 

blood-platelets (Leroy) . 



b, on edge; c, in rouleaux; d, 



In freshly drawn blood the red corpuscles are characterized by 
their color, their biconcave shape, and their tendency to form 
columns like rolls of coin. They consist of a homogeneous, semi- 
solid substance that breaks up under reagents into a colorless 
elastic stroma and a red coloring-matter. The white corpuscles 
are found in the spaces between the rolls of red corpuscles. They 
are grayish and globular. They consist of a transparent substance 







Fig. 86. — Various forms of leukocytes: a, Small lymphocyte; b, large lymphocyte; c, polymorphonu- 
clear neutrophile; d, eosinophile (Leroy). 

embedding granules — fatty, proteid, and carbohydrate. They 
have nuclei and are capable of ameboid movements. They can 
protrude and retract portions of their bodies, and thus envelop and 
expel foreign bodies. They can also squeeze through the walls of 
the capillaries. By staining they can be differentiated into four 
forms, believed to be stages in development (Fig. 86), small, large, 
36 



562 POODS AND DIGESTION 

mononuclear, polymorphonuclear, and eosinophile or " over-ripe" 
cells. The blood-platelets are distinct normal cells, grayish white 
and without nuclei. They appear to be involved with the cor- 
puscles in aiding coagulation. 

The red corpuscles are produced chiefly in the marrow of the 
long bones; the white are derived from the lymphocytes of the 
lymph-glands. The red corpuscles are carriers of oxygen; the 
white are the phagocytes or scavengers, destroying and removing 
particles of disintegrated tissue and the invading bacteria of disease. 

The blood coloring-matter is treated of in another place (p. 529). 

Blood=plasma is the colorless liquid which bears food to the 
tissues and in which the cellular elements float. In its 8.9 per cent, 
of solids the proteins constitute 6.9 per cent, and the inorganic 
salts 0.84, the remainder being carbohydrates, fats, and waste 
organic material. Sodium carbonate and disodium phosphate 
both contribute to give it an alkaline reaction. A proportion of 
phosphoric acid exists in combination with proteins. The protein 
substances are serum-albumin, serum-globulin (paraglobulin), 
and fibrinogen (metaglobulin). Varying amounts of oxygen and 
carbon dioxid distinguish arterial and venous blood. Oxygen to 
the extent of 0.26 per cent, is dissolved in the plasma; a larger 
amount, 22 per cent., circulates loosely, combined with the hemo- 
globin of the red corpuscles. Carbon dioxid to the extent of 40 
per cent, exists in the plasma, partly as alkaline carbonates and 
partly as a loose organic compound. In the act of breathing air 
comes to the walls of the alveolar capillaries. At the body tem- 
perature there is a high rate of diffusion between the gases of the 
alveoli and those in the blood. Oxygen constantly passes into the 
blood and carbon dioxid passes out. 

Coagulation. — While in the circulation, blood is a fluid of 
a specific gravity of about 1060. Soon after it is drawn from the 
vessels it suddenly becomes a solid jelly with a slight evolution 
of heat. On standing, the clot contracts, leaving a straw-colored 
liquid called serum. The clot itself is composed of corpuscles 
enclosed in a mesh of fibrin. Washing at the tap removes the cor- 
puscles and leaves the shreds of fibrin. Coagulation is due to a 
change in the dissolved fibrinogen (metaglobulin), brought about 
by the presence of calcium salts and an enzym — thrombose. Cal- 
cium is necessary for clotting. The ferment appears to cause a 
combination of the fibrinogen with the calcium, resulting in the 
coagulated protein. As the fibrin comes out of the plasma, there 
is left the serum. This retains two proteins — albumin and glob- 
ulin — and the enzym — thrombase. If magnesium sulphate be 
added to saturation, the globulin is precipitated. After filtration 
the filtrate contains albumin, which is precipitated by saturation 



BLOOD 563 

with ammonium sulphate. After filtration of this precipitate the 
filtrate does not respond to tests for proteins — i. e., nitric acid, 
heat, and the biuret reaction. 

Biologic Test. — In another place (p. 523) definitions have 
been given of the terms hemolysin and precipitin. When an albu- 
minous substance from one animal is injected into another of 
different species, "antibodies" form, which precipitate it. This 
precipitin is specific for that albumin and distinguishes it from all 
others, even when by ordinary chemical or physical reactions no 
difference can be detected. After cows' milk has been injected into 
the peritoneum of a rabbit the serum of the rabbit precipitates 
the casein of cows' milk, but has no effect on the milk of other 
animals. When a rabbit has been immunized by repeated injec- 
tions of small quantities of human blood, peculiar hemolysins and 
precipitins are found in the blood-serum of the rabbit. This 
serum has a hemolysin which disintegrates human blood-corpuscles 
and precipitates dilute human serum when in the proportion of 
1 : 100, but not that of the ape until the concentration is 1 : 30, 
nor that of the dog until it reaches 1 : 10. It appears that though 
the precipitin is specific, the blood of other animals may show 
some proportions of it, according to the closeness of their rela- 
tionship. By means of this test blood-stains can be traced to their 
origin in man or in some species near him in the animal scale. For 
this purpose the stain is dissolved in 0.9 per cent, salt solution and 
filtered. 

Experiment 1. — Defibrinated blood may be obtained at the 
slaughter-house by whipping freshly drawn blood with a bundle 
of twigs. The fibrin collects on the twigs and the remaining 
blood keeps fluid. Test the reaction with neutral litmus paper. 
After washing away the blood a blue stain shows alkalinity. 

Experiment 2. — Put in a test-tube 5 c.c. of hydrogen peroxid, 
add a few drops of blood, and note the foam caused by oxygen 
bubbles escaping from the peroxid. The blood is a catalytic agent, 
from the presence of catalase, and also from a peroxidase (p. 538). 

Experiment 3. — Guaiac Test. — Put a small lump of freshly 
broken gum guaiac into a test-tube containing alcohol and boil 
until deep yellow. Filter and add filtrate to dilute blood to make 
an emulsion. Pour in gently hydrogen peroxid; a blue ring forms. 
If the quantity of blood is small, then a few drops of the emulsion 
is added to a fragment of sodium perborate on a white plate. The 
fragment turns blue and changes later to green. 

Experiment 4. — Having dried a drop of blood on the slide of 
a microscope, add glacial acetic acid, cover, and warm until bub- 
bles appear. On examination Teichmann's hemin crystals are 
seen (Plate 4, Fig. 3). 



564 FOODS AND DIGESTION 

Experiment 5. — With a spectroscope note the changes in the 
absorption bands induced by deoxidation of diluted blood with am- 
monium sulphid and gentle heat. Observe the return of bands 
after pouring the blood back and forth several times to get oxygen 
from the air. Saturate with coal-gas and note that the bands now 
are not changed by ammonium sulphid, as the carbon monoxid 
hemoglobin is a fixed compound not susceptible to reduction and 
oxidation (Plate 4, Fig. 1, e.) 



EXAMINATION OF MILK 

Properties. — Normal milk is a sweet, opaque, bluish-white 
fluid, with a peculiar odor, holding in solution caseinogen, albu- 
min, sugar, and mineral salts. Its opacity is due to the minute 
butter globules which are suspended in it. 

Percentage composition of normal milk. Cow. Human. 

Water 87.41 87.29 

Solids, as tabulated below I2 -59 12.71 

Caseinogen 3.01 1.03 

Albumin 0.75 1.26 

Albuminoids 3.76 2.29 

Butter or fat 3.66 3.78 

Milk-sugar 4.92 6.04 

Ash 0.70 0.31 

Microscopically, the milk is composed of minute, brilliant fat- 
globules suspended in clear plasma. Immediately after birth of 
the child human milk is relatively poor in casein, but rich in fatty 
matter, which exists in the form of colostrum masses (Fig. 87). 

Morbid Milk. — Human milk is injured by excessive emotion 
or ill-health of the mother and by the administration to her of 
certain drugs that pass into the milk. Cows' milk is affected in 
the same way by diet and by disease, such as tuberculosis, foot- 
and-mouth disease. 

Reaction. — Human milk turns red litmus paper blue, show- 
ing alkalinity. Cows' milk is usually alkaline or neutral when 
fresh, though sometimes acid when delivered in cities, and occa- 
sionally a sample will be found that is amphoteric — that is, red- 
dens blue litmus paper, and turns red litmus paper blue. This is 
ascribed to the presence of the acid phosphates which dissociate 
hydrion with the secondary phosphates, which are alkaline from 
the hydroxidion they dissociate by hydrolysis (p. 188). 

Quantity. — The average secreted daily by a woman is 1 L., or 
2 pt. 

Spontaneous Change. — If milk stand for several days in a warm 
place, it coagulates and sours — that is, turns acid by fermentation 



EXAMINATION OF MILK 



565 



of the sugar (lactose) into lactic acid, C 6 H 12 6 = 2(C 3 H 6 3 ). The 
coagulum consists of casein, which previously existed in a soluble 
form of union with calcium phosphate as caseinogen. This curd of 
casein can be produced by any acid, as in the following experiment: 

Experiment 1. — Acid Curd. — To half a test-tubeful of diluted 
milk (1 : 3) add a drop or two of acetic acid, and gently warm; an 
abundant precipitate falls. This precipitate is the curdled casein, 
carrying with it most of the fat. 

Experiment 2. — Put into a test-tube 1 c.c. of milk and 20 c.c. of 
water. Add a few drops of solution of copper sulphate and a few 
drops of potassium or sodium hydroxid to throw down the proteins 
and fat. When the precipitate falls, decant or filter off the clear 
liquid. Boil this with Fehling's solution: a red or yellow precipi- 
tate means sugar (lactose). 

Experiment 3. — Proteins. — Mix equal volumes of milk and 
Millon's reagent in a test-tube and boil. A red precipitate proves 
the presence of proteins (casein and albumin). 

Milk=SUgar and Salts.— Having filtered the whey from the 
acid curd and tested the fil- 
trate with Fehling's solution, it 
is seen that the milk-sugar re- 
duces the cupric salt and pre- 
cipitates the yellow or red oxid. 
If to another portion we add 
magnesia mixture, the phos- 
phates are precipitated. On 
adding to another portion silver 
nitrate, the chlorids are precip- 
itated, insoluble in nitric acid. 

Butter. — In cows' milk 
ether will not dissolve the fat- 
globules unless they are lib- 
erated by removing their en- 
velopes with acetic acid, caustic 

potash, or soda. With human milk it suffices to agitate vigor- 
ously with ether alone. In churning, the envelopes of casein are 
ruptured mechanically, and the fat-globules cohere in large masses 
of butter. This process does not separate all the fat as butter. 
The residue, called buttermilk, still contains about 1 per cent, of 
fat. As it is formed from ripened cream, buttermilk contains 
lactic acid formed at the expense of the lactose. We may separate 
the fat by the following experiment: 

Experiment. — To a test-tube one-third full of milk add half its 
volume of potassium hydroxid and half of ether; shake the mixture 
and stand in a warm place. The milk clears up, and the butter 




Fig. 87.-0, Milk; b, colostrum (Wolf). 



566 FOODS AND DIGESTION 

dissolved in the ether floats at the top. By separating the ethereal 
layer and evaporating it, a residue of butter is left. 

Pepsin Curd. — The first act in the digestion of milk is the con- 
version of caseinogen to casein, and its coagulation by the rennin 
of the gastric juice. This can be shown artificially by the following 
experiment: 

Experiment. — Into a test-tube about one-third full of milk put 
a few drops of neutral essence of pepsin (Fairchild's). Mix gently, 
warm to the temperature of the body, and keep at 40 ° C. (104 F.). 
A solid curd, containing fat entangled by the casein, forms in ten 
or twelve minutes, so that the tube can be inverted without losing 
the milk. In a short time a whey separates from the clot. If the 
experiment be performed on human milk, the coagulum is not a 
lump of curd, but floating flocculi. If cows' milk be boiled or if it 
be largely diluted with lime-water, the same loose flocculi form 
when it is curdled with pepsin. 

Experiment. — Add a few drops of dilute hydrochloric acid to 
the pepsin curd, so as to make with the pepsin an artificial gastric 
juice, and set aside at 40 C. (104 F.) for two or three hours. 
The curd is digested and gradually dissolves to make a yellowish 
fluid with the peculiar odor and bitter taste of peptonized milk. 

If the milk be previously boiled, or if the rennet be boiled, the 
ferment will not work. 

In the creameries the curds are a by-product from which alkali 
or sodium combinations with casein are produced and used as 
condensed foods under the names " plasmon' ' and " nutrose.' ' 

Methods of Preservation.— To prevent the lactic-acid and 
other fermentations, several procedures are resorted to, such as 
refrigeration, sterilization, pasteurization, and the addition of pre- 
servatives. 

Refrigeration. — If a sample of fresh milk, tested with litmus 
paper, be put in a refrigerator kept at or below 10 ° C. (50 ° F.) 
for several days, the reaction will be but little changed, the milk 
having kept sweet and uncurdled. Cold will not preserve milk 
indefinitely, nor will it kill bacteria, nor alter toxalbumins after 
they have been formed. 

Sterilization. — Fresh milk boiled for twenty minutes forms a 
scum, due to coagulation of the lactalbumin and globulin. By 
excluding the floating dust of the air with a plug of cotton, it will 
keep sweet and uncurdled for several days, owing to the death of 
the bacteria which cause lactic fermentation. So far as infection 
is concerned, milk sterilized by boiling is perfectly safe; at the same 
time the fats, sugars, casein, and albumin are altered in such a way 
as to make boiled milk less digestible and nourishing than raw 
milk. A lower degree of heat will suffice to prevent the growth 



EXAMINATION OF MILK 567 

of bacteria for a short while and not injure the milk as an assimilable 
food. 

The temperature sufficient for the destruction of the tubercle 
bacillus is 68° C. (154 F.); for the typhoid bacillus, from 55 ° to 
6o°C. (i3i°-i40°F.j;and for the diphtheria bacillus, about 58 C. 
(137 ° F.j. Most of the saprophytes will be killed at a temper- 
ature of 65°to 75 C. (i49°-i67° F.). It is clear, then, that if we 
heat milk to a temperature of 68° to 75 ° C. (i54°-i67° F.), we do 
not materially alter its taste and digestibility, but we render it 
practically germless. Bitter and Freeman have each found 68° to 
69 ° C. (i54°-i56° F.) the suitable temperature for the purpose. 

Milk heated above 75 ° C. (167 ° F.) is so changed that chil- 
dren fed on it exclusively do not thrive. It is probable that there 
are several enzyms in milk, such as milk trypsin or galactose and 
milk catalase, which are favorable to its digestion and which are 
rendered inactive above this temperature. 1 Below 75 ° C. (167 ° 
F.) it does not lose the taste of fresh milk nor become less diges- 
tible. At this temperature and as low as 65 ° C. (150 F.) the 
matured disease germs are killed and the spores so much weak- 
ened in vitality that all liability to cause intestinal disorder is re- 
moved if the milk be used within twenty-four hours of the treatment. 

This process was devised by Pasteur and bears his name; its 
value may be tested by the following experiment: 

Pasteurization. — Having put some fresh milk in a clean glass 
bottle, stoppered with a plug of cotton, stand it in a vessel of water 
and heat the water to 70 ° C. (160 F.) for a few minutes, observing 
the temperature by an immersed thermometer. It will be found 
to keep sweet for twenty-four hours at least. 

Freeman's Pasteurizer. — A simple apparatus which any nurse 
can use with accurate results is the pasteurizer devised by Free- 
man. It consists of a metal pail, into which fits a receptacle hold- 
ing the bottles. The receptacle is so made that each bottle fits 
into a separate small metal cylinder. The pail is filled with water 
to the level of the groove running around it, placed on the stove, 
and the cover put on. The proper amount of milk for each feeding 
is put into each bottle, the bottles plugged with raw cotton, and 
placed in the receptacle. Water is then poured around them into 
each cylinder, in order to prevent the direct action of the hot water 
in the pail from cracking the bottles. As soon as the water in the 
pail is boiling, the pail is removed from the fire and placed out of 
the draught upon a non-conducting substance. The lid is now re- 
moved, the receptacle put in , and the lid reapplied. It is left thus 

1 A constant constituent of unheated milk is an oxidizing enzym. Its absence 
may be regarded as proof that the milk has been heated for preservation. The test 
for it is to mix with 10 c.c. of milk 1 c.c. of fresh tincture guaiac, 5 c.c. of turpen- 
tine, and 5 c.c. of hydrogen dioxid. Unheated milk gives a blue color. 



568 FOODS AND DIGESTION 

for forty-five minutes, when the lid is removed and the receptacle 
elevated so that it rests upon supports which hold it partially out of 
the pail, and a stream of cold water is now turned into the pail 
for fifteen minutes. The bottles are then kept on ice till needed. 
The principle of the apparatus is the fact that the given quantity 
of water which is in the pail will, in cooling, elevate the temperature 
of the milk to the desired degree, so that the two liquids become of 
the same temperature at 68° to 69 C. (i54°-i56° F.). Receptacles 
are made either for 10 six-ounce bottles or 7 eight-ounce bottles, 
and either receptacle will fit into the pail. 

In the absence of a thermometer or special apparatus, resort 
may be had to the following rough method: A basin containing 
several inches of water is placed on a slow fire and the cotton- 
stoppered bottles of milk placed in it. After boiling the water for 
ten minutes the milk, which has not boiled, but only simmered, is 
removed and kept in a cool place until used. 

If the milk be not tolerably fresh, poisons may have developed 
already. Pasteurizing will not destroy the toxalbumins or dissolved 
poisons when once produced, nor render stale milk harmless. 

Test for Pasteurized or Sterilized Milk. — Heat two samples of 
milk, one, A, to 70 C. (160 F.), the other, B, to 8o° C. (176 F.). 
When cold, test both separately by adding to each a small amount 
of solution of paraphenylendiamin (C 6 H 4 (NH 2 ) 2 ), and then a few 
drops of hydrogen dioxid. The unchanged enzyms in A cause 
instantly a deep-blue color; the overheated B does not turn blue 
for some time. 

Preserved Milk. — To prevent bacterial changes in milk it is 
quite common to add formaldehyd or boric acid, either of which 
is tasteless in the amounts used. 

Formaldehyd is usually added as formalin, under the trade 
names of Preservalin and Freezene, in the proportion of 1 : 40,000, 
less than 5 drops in a gallon. While it certainly enables milk to 
be kept longer in warm weather, there is some evidence to the 
effect that it retards slightly the digestion of protein material, 
although without any injurious general effect. 

Boric acid and borax are employed as preservatives by adding 
to 1 qt. of milk 10 gr. of mixture of equal parts of borax and boric 
acid, or 35 gr. of boric acid to the gallon. 

It is not likely that this amount would cause injury to the average 
healthy adult, taking an ordinary quantity of milk with other food, 
but it would very likely lessen the digestibility if not prove hurtful 
in the case of invalids and infants (p. 209). 

Salicylic acid in milk may be detected by precipitating fat and 
proteins with mercuric nitrate and acetic acid, filtering and agi- 
tating the filtrate with ether, which dissolves the salicylic acid. 



EXAMINATION OF MILK 569 

After separation, the ethereal solution is evaporated and yields the 
acid in crystals. These are dissolved in alcohol and tested by 
ferric chlorid, which gives a violet color; or else they are heated 
with a mixture of methyl alcohol and sulphuric acid, when the 
odor of wintergreen reveals the presence of salicylic acid. 

In a similar manner benzoic acid is separated and identified by 
its reaction with ferric chlorid or cupric sulphate. 

Detection, of Formaldehyd in Milk. — Boil the suspected sam- 
ple, 1 part, with 4 parts of commercial or yellow hydrochloric acid, 
which contains a trace of a solution of ferric chlorid. If no purple 
color result on cooling, dilute with an equal part of water, add a 
trace of ferric chlorid, and boil again. The purple reaction will 
sometimes appear better in the weaker solution. 

Hehner's Test. — The same reaction follows the test made by 
mixing 1 c.c. each of milk and water, and pouring the mixture 
gently on 4 c.c. of strong commercial sulphuric acid which has a 
trace of ferric sulphate or chlorid. If the sulphuric acid is pure, add 
a drop of solution of ferric chlorid. The line of contact is blue or 
purple when formaldehyd is present, but with pure milk ii is green. 
This reaction is due to the protein of the milk in the presence of a 
minute quantity of formaldehyd. It will detect 1 part of the latter 
in 250,000, and shows better when the proportion of protein is 
large. Hence if the purple does not appear at first, dilute the 
milk with thinned milk of known purity, and try again. 

Detection of Boric Acid or Borax by the Turmeric Test. — Place 
in a porcelain dish 1 drop of the milk with 2 drops of strong hydro- 
chloric acid and 2 drops of a saturated turmeric tincture. Dry the 
mixture on a water-bath; cool, and add a drop of ammonia by a 
glass rod. A slaty-blue color, changing to green, indicates borax. 
A drop of milk containing two g r - °f borax will give this reaction. 

Specific Gravity. — The hydrometer employed for taking the 
specific gravity should be very accurate and carry a scale for the 
usual variations of milk, or between 1000 and 1040. The lac- 
tometer of the New York Health Board is a hydrometer with a scale 
on which 100 ° stands for a specific gravity of 1029 (the minimum 
density of pure milk), while o° stands for the specific gravity of 
water, and 120 for 1034, the maximum range of pure milk. On 
this instrument i° is read as 1 per cent, of milk in the sample. 

For cows' milk care should be taken to shake cream and milk 
together before testing. 

To suit the small amount with human milk smaller instru- 
ments are used. 

The sample taken for examination should be from the middle of 
the nursing or when the breast has been about one-half emptied, as 
the first milk is always poorer and the last richer than the average. 



57° 



FOODS AND DIGESTION 



The specific gravity should be taken at a temperature of from 
i8° to 23 ° C. (65°-72° F.). By giving the stem of the lactometer 
a twirl as it is introduced, it readily settles to the proper level, which 
may otherwise be prevented by the adhesion of the milk to the 
glass, especially in a rich specimen. 

The specific gravity of dairy milk, the product of a number of 
cows, should never fall below 1029. When lower than this, it is 
usually due to adulteration with water; but very rarely the low 
density is due to excess of cream in very rich milk. 

The quantity of cream is measured by an instrument known 
as a creamometer, or a 10 c.c. glass-cylinder graduate may be used. 
Having mixed the milk thoroughly, a sample is poured into the 
vessel up to the highest mark. After twenty-four hours, at a tem- 
perature between 15 ° to 24 C. (6o°-75° F.), the depth of cream 
layer thrown up is red, each degree of the scale being 1 per cent. 
The average sample of cows' milk would be 12 per cent. If the 
cream form 20 per cent, of the column, the sample would probably 
also show a low specific gravity. The accuracy of this test is 
affected by the length of time since milking, by the amount of 
previous agitation of the milk, by the fact that dilution causes a 
more rapid separation of the cream, by the temperature, and other 
variable conditions. It may serve a useful purpose when taken 
in consideration with other observations. In sorting cows' milk 
it may be assumed that: 

Less than 10 per cent, of cream in a milk of specific gravity above 
1033 denotes skimming. 

Less than 20 per cent, of cream, if joined to a specific gravity less 
than 1020 indicates watering. 

Clinical testing of mothers' milk is usually confined to taking 
the specific gravity with a small special lactometer and the per- 
centage of cream in a small 10 c.c. graduate. 





Human Milk 




Specific gravity, 
7o°F. 


Cream — 24 hours. 


Proteins. 


Normal average 


1.031 


1% 


1.5%. 


Healthy variations 


1. 028-1. 029 


9%-I2% 


Normal (rich milk). 


•i a 


1.032-1.033 


S%- 6% 


" (fair milk). 


Unhealthy " 


Below 1.028 


High (above 10 ^ ) 


" or slightly below. 


" " 


1.028 


Normal (5%-io%) 


Low. 


« << 


" 1.028 


Low (below $%) 


Very low (very poor milk). 


<( << 


Above 1 .033 


High 


Very high (very rich milk). 


" " 


" 1.033 


Normal 


High. 


(< t( 


" L033 


Low 


Normal (or nearly so). 



Human milk presenting only moderate variations from the average — e. g., specific 
gravity 1.028, cream 4 per cent., or specific gravity 1.033, cream 10 per cent., can 
usually be modified by appropriate treatment. If, however, the specific gravity is 
from 1. 018 to 1.024, and the cream only 2 per cent, to 3 percent., it is hopeless 
(Holt). 



EXAMINATION OF MILK 



571 



The lactoscope of Feser gives good results for ordinary test- 
ing of milk to determine its richness. The opacity of milk is 
due to the fat-globules, and is proportionate to the number of 
them. By measuring this opacity an approximate estimate can be 
made of the percentage of fat. For making this estimate roughly 
the lactoscope is very convenient. In the axis of 
a cylindric clear glass vessel (Fig. 88) and at its 
lower part (A) is a smaller cylinder of white 
glass, marked with a few black lines. In test- 
ing with this instrument, 4 c.c. of milk are intro- 
duced with the graduated pipet; the black lines 
are entirely concealed. Pure water is gradually 
added, while shaking, until the milk clears up 
sufficiently to make the black lines distinctly 
visible. There is a range of 1 per cent, be- 
tween the point where the lines are first seen 
and that where they become sharply defined. 
By the graduation on the vessel the surface level 
of diluted milk can be read as percentage of fat 
in the original sample. The microscope having 
determined the absence of chalk, starch, or other 
suspended adulterants, a sample showing 3 per 
cent, and over is judged pure. Some rich Jersey 
milk shows 6 per cent. Any one experienced in 
its use will be accurate to within \ of 1 per cent. 
The main point is to see the lines well defined 
and not hazy. Having obtained the specific 
gravity by the lactometer, and the percentage 
of fat by the lactoscope, experiment shows that 
the proportion of total solids can be calculated by the formula of 
Hehner and Richmond. 1 

A much simpler and less accurate method was devised by 
Heeren, whose pioscope consists of two disks. One of them is 
made of hard black rubber, in the center of which is a shallow, 
flat cell, of 22 mm. diameter, surrounded by a ring of 0.5 mm. 
in height, intended for the reception of a few drops of the well- 
mixed milk. The other disk is made of glass, colorless in the 

i X _F-f 0.2186 G 




Fig. 88. — Feser's lacto- 
scope. 



O.859 

in which F stands for percentage of fat, T, the percentage of total solids, and G, the 
specific gravity expressed in the last two units and any decimal ; thus, if the specific 
gravity is 1028.5, tn en G stands for 28.5. For example, if a specimen of milk had 
a specific gravity of 1030, and the percentage of fat was 4, then — 

Total solids = 4+ (° 2186 X3Ql = I2 , cent 
0.859 V 



572 



FOODS AND DIGESTION 



center as far as is necessary to cover the central cell of the rubber 
disk, while on the margin are represented, in six sections, the 
various tints of cream, and milk from very rich to very poor. A 
comparison of the color of the milk in the central cell with the 
marginal color standards is rapidly made and gives results suffi- 
ciently approximate for the preliminary testing. 

If a specimen of milk fail to satisfy the requirements of these 
physical tests, or if it become desirable to investigate more 
thoroughly for any other reason, the more exact methods of 
examination in the laboratory must be resorted to. 

The creamometer of Chevelier (Fig. 89), or one of its modifi- 
cations, may be used for this purpose. In this instrument the milk 
is left at rest for twenty-four hours to give time for the cream to rise, 
whose volume is then measured and readily shows whether the 
milk has been tampered with. After measuring and removing 
the cream the specific gravity of the residue may be taken, and 
shows by its lack of proper density the addition of water. In its 
simplest' form the creamometer is a glass cylinder of about 35 mm. 
diameter and 170 mm. height. Measuring from below, marks are 
made, running around the cylinder at 50 c.c., 100 c.c, and 150 c.c. 
The interval between 100 and 150 is divided into 30 equal parts 
by short lines of division, and this graduation is ex- 
tended to 10 of these units above 150 and below 100. 
Thus, the upper half is divided into 50 equal parts. 

3 Milk is poured into the instrument up to the upper- 

10 most mark of graduation, which also runs around 
l ° w the cylinder. After leaving it at rest for twenty-four 
hours the supernatant cream is measured, each unit 
of the graduation corresponding to 1 per cent, by 
volume. Good milk should not yield less than 10 
per cent, of cream. After removal of the cream, the 
specific gravity of the residue is increased by 0.020 
to 0.035 of the specific gravity of the fresh specimen 
before separation of the cream. A less voluminous 
layer of cream than ten subdivisions indicates that cream has been 
abstracted, and a smaller increase of the specific gravity indicates 
the additional dilution with water. The means of applying this 
test are simple enough, and it fairly approximates the true con- 
dition, but requires too much time to commend itself as a pre- 
liminary examination to be left to the subordinate inspectors. 
To reach close approximations with simple apparatus in a brief 
space of time, the optical behavior of milk is examined by Feser's 
lactoscope. 

Modified milk is cows' milk altered by dilutions and addi- 
tions in such a way as to bring its composition nearer to that of 



Fig. 89. — Cream 
ometer. 



EXAMINATION OF MILK 573 

human milk. The difference in the proportion of the two proteins, 
caseinogen and albumin, causes cows' milk to be less digestible 
in the human stomach. The gastric juice makes with human milk 
a slight flocculent curd, easily dissolved in the digestive juices. 
This is due to the small amount of caseinogen, which is the only 
protein coagulated by rennin. As cows' milk contains four times 
as much caseinogen and one-half as much albumin, it forms a 
tough, abundant curd of difficult solubility. 

It is not possible artificially to produce the right proportion of 
the two proteins, but we can lower the proportion of caseinogen 
by dilution w r ith w r ater. Human milk averages about 2 per 
cent, more in sugar. Other differences, such as the alkaline re- 
action, will be noted on referring to the Tables of Composition at 
the beginning of this chapter. In the milk laboratories cows' 
milk is modified to resemble human milk by mixing milk, cream, 
lime-water, water, and milk-sugar in the right proportion for the 
age of the child. The exact formula varies according to the 
period of lactation, but an average human milk is closely imitated 
by a mixture of milk, 2 fl. oz.; cream, 3 fl. oz.; water, 10 fl. oz.; 
lime-water, 1 fl. oz.; and milk-sugar, 4 dr. It is customary to 
pasteurize the mixture and deliver it fresh in bottles stoppered 
with plugs of cotton to exclude bacteria. 

When it is not convenient to have the milk mixture made at 
city laboratories, the mother w T ill find useful a special glass graduate, 
called " Materna," which holds from 16 to 24 fl. oz. The outer 
surface is divided into seven vertical panels, and each of these is 
marked to show how much milk-sugar, milk, cream, lime-water, 
and water shall be mixed to get a product of a certain desired 
percentage strength for an infant of a certain age. The panels 
also show the percentages of fat, protein, and sugar in the meas- 
ured amounts of the ingredients. The first is marked "fat 2 per 
cent., protein c.6 per cent., sugar 6 per cent.," making a formula 
to be used at the beginning of an early weaning. The second 
panel is marked "fat 2.5 per cent., protein 0.8 per cent., sugar 6 
per cent.," and the other panels show progressively increasing 
strengths. 

Milk Standards. — By the United States Treasury Depart- 
ment, cows' milk should contain by weight not less than 13 per 
cent, of solids and not less than 3.5 per cent, of fat. In Philadel- 
phia it must have not less than 12 per cent, of solids nor less than 
3.5 per cent, of fat. By the State of Pennsylvania it is required 
to contain not less than 12.5 per cent, of solids and not less than 
3 per cent, of fat. In the States of New York and New Jersey it 
should contain not less than 12 per cent, of solids, nor less than 
3 per cent, of fat. The English Society of Public Analysts has 



574 FOODS AND DIGESTION 

fixed the standard for Great Britain as follows: Total solids, 11.5; 
fat, 3; solids not fat, 8.5 per cent. 

Total Solids by Weighing. — The determination of total solids 
gravimetrically consumes considerable time, but it gives accurate 
results. Into a tared dish of platinum or a watch-glass 5 gm. of 
milk are weighed or 5 c.c. measured. The dish is then exposed 
to the heat of a water-bath for three hours. As evaporation is 
nearly done, it is now put into a water oven, and at intervals 
weighed until it ceases to lose weight. This constant weight, less 
the weight of the capsule, gives the total solids. The difference 
between the 5 gm. and the constant weight of the dry solids rep- 
resents the water. By carefully incinerating the solids to a grayish- 
white color the ash or inorganic salts are determined. In pure 
milk the amount ranges from 0.7 to 0.8 per cent. A watered 
milk will show a reduced amount both of solids and of ash. 

Determination of Fat (Werner- Schmid Process). — This is an 
easy and quite accurate method. Into a long test-tube with a 
capacity of 50 c.c, and graduated to show cubic centimeters in tens, 
measure 10 c.c. of milk and 10 c.c. of strong hydrochloric acid. 
(A large common test-tube can be used, and the measurement 
made by pipets or other graduated glasses.) The mixture of acid 
and milk is boiled one and one-half minutes, or the tube may be 
corked and heated in a water-bath for five or ten minutes, until 
the liquid turns a deep brown, but not black. Having cooled the 
tube and its contents in running water, 30 c.c. of well-washed 
ether must be added, the tube corked, the mixture well shaken, 
and finally stood aside. When the line of separation between the 
ether and acid is distinct, a wash-bottle cork stopper with its tubes 
is substituted for the plain stopper (see Fig. 90). 

The lower end of the exit tube has a short curve, which is ad- 
justed so that its opening is just above the line of separation. A 
weighed flask or beaker is held so as to receive the ethereal layer 
when it is blown out by the lips at the upper tube. In succession 
two additional portions of washed ether, 10 c.c. each, are shaken 
with the acid and blown out into the weighed flask. The ether is 
then distilled off or evaporated, and the fat residue dried in a water 
oven and weighed. It is the amount contained in 10 c.c. of milk. 

Babcock's Method with Centrifuge. — For separation of fat from 
either human or cows' milk the graduated milk bottle (Fig. 91) 
may be used with any medical centrifuge (p. 577). It gives results 
accurate to within 0.2 per cent, of fat. It is a simple method and 
the manipulation is easy. 

Two pipets are supplied with the bottles, one of 5 c.c. capacity; 
the other holding 1 c.c. up to a mark on the lower stem, for intro- 
ducing the alcoholic solution. 



EXAMINATION OF MILK 



575 



To determine fat by this method the sample, well mixed, 
should be taken from the middle portion of the nursing or milk- 
ing — as the first milk is poorer and the last richer than the average. 
Five cubic centimeters of the sample are introduced into the milk 
bottle by means of one pipet; i c.c. of alcoholic solution (which 
consists by volume of amyl alcohol, 37; wood alcohol, 13; hydro- 
chloric acid, 50) is added by the other, and the bottle shaken by 
hand. Then by means of the large pipet strong sulphuric acid, 
specific gravity 1.83, is added little by little, with shaking, until 
the bottle is filled to the brim. When whirled in the centrifuge 
two minutes, the fat rises to the neck in a clear yellowish layer, 
and can be read oft" in direct percentages. If the level of the 




Fig. 90. — Werner-Schmid 
process. 



Fig. 91. — Milk bottle for 
centrifuge. 



Fig. 92. — Pipet for 
milk. 



fat should be below the zero point as the result of the cooling, a 
few drops of water should be added to raise it. Another whirl 
of the centrifuge will carry the water below the fat layer and 
lift the latter to the desired point. If the milk should be richer 
than 5 per cent., add 5 c.c. of water to 5 c.c. of milk, mix 
thoroughly, take 5 c.c. for analysis, and multiply the result by 2. 

For cream add 20 c.c. of water to 5 c.c. of cream, mix, take 
5 c.c. for analysis, and multiply the result by 5. 

The alcoholic solution can be kept some weeks. If it turn 
dark, a fresh mixture must be made. 

By Weighing. — To determine the butter by the gravimetric 
method, 10 gm. of milk are weighed into a tared dish containing 
a weighed amount of dry sand. The milk is evaporated on a 



576 



FOODS AND DIGESTION 



water-bath and last on a water-oven, with constant stirring. The 
residue is washed a number of times with warm ether 
or petroleum naphtha of specific gravity 70 ° Baume, 
and the washings passed through a small filter. The 
filtrates are all received in a tared beaker and care- 
fully evaporated to a constant weight. The residue is 
jat. This subtracted from the amount of total solids 
gives the solids not jat. 

Adams 1 Method. — This is the standard process in 
use by official chemists who have well-equipped labo- 
ratories. The milk is absorbed by strips of pure, 
fat-free paper, which distributes the milk-fat in a thin 
layer. The coiled strip is dried in a water oven, and 
then placed in the middle chamber of a Soxhlet ex- 
tractor (Fig. 93). The tared flask, containing 75 c.c. 
of ether, is heated on a water-bath. 

Ether vapor condenses in the upper apparatus, 
flows back upon the coil of paper, and returns to 
the flask. After ten such washings the flask con- 
taining the ether is detached and connected with 
a condenser. After distillation, the fat residue is 
dried in an air oven, cooled, and weighed. 



PRACTICAL URINARY EXAMINATION 

Ordinary Examination.— As this section is concerned with 
the knowledge which has value to the medical practitioner, it is 
deemed best to limit its range to those points which have practical 
significance. 

A good working plan for the ordinary analysis need not in- 
clude more than the following procedures, and in most cases less 
than the total of these will serve every requirement: 

Measurement of the daily quantity. 

Noting the color: if deep yellow, green, or brown, testing for 
biliary pigment; if reddish, smoky, or chocolate-hued, testing for 
hemoglobin. (Plate 7.) 

Taking the reaction. 

Determination of specific gravity with the hydrometer. 

After the sediment falls, decanting the clear part and examin- 
ing for albumin by boiling and by adding acid — nitric, picric, or 
acetic. If greenish flakes form, bile pigment is to be looked for; 
if red-brown, then hemoglobin. After twenty-four hours noting 
the height of albuminous layer. 

Testing for glucose by Fehling's and by Bottger's methods, 
with calculation of the amount. 



THE URINE 



577 



Estimation of the relative amount of chlorids. 

Estimation of the amount of urea. 

Noting the naked-eye appearance of the deposit which forms 
on standing for several hours. Making allowance for the light 
cloud of epithelial debris sometimes found in health, a sample 
voided turbid and acid points to urates or mucus or pus or blood; 
if voided turbid and alkaline, it points to phosphates. (Plate 7.) 

Careful examination of the deposit with the microscope, using 
a J or -§- objective and an eye-piece giving a magnifying power of 
about 250 diameters. The search should be made for phosphates, 
calcium oxalate, uric acid, urates, epithelium, pus, tube-casts, 
spermatozoids, blood-cells, leucin, tyrosin, cystin, organisms such 
as sarcinae, the molds, and bacteria; and in addition such extra- 
neous substances as sometimes enter the 
bladder by fistula from the rectum. 

For minute study of the bacteria it 
is necessary to stain the sediment and 
use the high power of 900 diameters 
obtained with immersion lenses. The 
illumination should be by substage wide- 
angle condensers. If the absence of 
organic or definite crystalline structure 
leave a doubt as to the nature of a 
deposit, the following simple tests may 
prove serviceable: First, warm a portion 
of the deposit with some urine in a test- 
tube: if it clear up, then the urates are 
present; if it do not clear up, then sus- 
pect phosphates. Second, warm a fresh 
portion with acetic acid: if it dissolve, 
phosphates are present. 

Precautions as to the Sample. — 

The microscope often shows substances 
which, being extra-urinary, may be 
broadly described as dirt, having no 
significance whatever. Owing to ignor- 
ance or carelessness on the part of patient or nurse, it not infre- 
quently happens that floating dust or sweepings or fecal matter 
get into the vessel, or sometimes an unclean bottle may make 
its contribution. Hairs, cotton, and linen fibers may be mis- 
taken for tube-casts, while such objects as large globules of free 
oil, starch granules, and vegetable cells are obviously extraneous. 
To avoid fallacies it is well to enjoin care upon the patient or 
nurse to have the container sterilized by a hot solution of calx 
chlorinata. The urine should be voided into a well-cleaned 




Fig. 94.— Hand centrifuge. 



57 



57§ FOODS AND DIGESTION 

chamber-vessel, or, better still, into a glass collecting-jar suffi- 
ciently large to hold the entire daily amount. By means of a 
clean glass funnel about 8 fl. oz. should be transferred to a bottle 
or, if in hospital, to a conic glass. 

Before taking up a drop of the deposit with the pipet, for 
examination with the microscope, sufficient time must be allowed 
for the sediment to collect. As a rule, this will require that the 
sample should stand for about three hours, but if rotated in a 
centrifuge, separation will occur in three minutes. If the amount 
of the spontaneous deposit be small, it can be concentrated by 
decanting the clear fluid and using the centrifuge upon the sedi- 
mentary portion. 

To get the best results from the centrifuge the bearings should 
be lubricated, violent rotation avoided, and the arms balanced 
by carrying equal loads of the fluid. The readiness with which 
urine undergoes change is a noteworthy fact. The liability 
varies in different specimens. Even a healthy urine may in a few 
hours after micturition increase in acidity, owing to the change 
of the common soluble urates to the more acid and less soluble 
salts, which are precipitated along with more or less free uric 
acid. 

2 (NaH 2 P0 4 ) + Na 2 H 2 C 5 N 4 3 = 2 (Na 2 HP0 4 ) + H 4 C 5 N 4 3 

Acid phosphate. Sodium urate. Neutral phosphate. Uric acid. 

The destiny of the urea in all specimens kept several days in a 
warm place is to be converted into ammonium carbonate by the 
growth of the Micrococcus urea and its enzym, urase. 

CO.N 2 H 4 + 2 H 2 = (NH 4 ) 2 CO s 

Urea. Water. Ammonium carbonate. 

This change may take place in the bladder if the urine be re- 
tained too long, and may cause grave complications in vesical dis- 
eases. 

The urine itself becomes turbid, putrid, and irritating, throwing 
down a deposit of phosphates with urate of ammonium. 

(NH 4 ) 2 C0 3 + 2MgHP0 4 = 2(MGNH 4 P0 4 ) + H 2 CO s . 

Ammonium carbonate. Magnesium phosphate. Ammoniomagnesium 

phosphate. 

To correct this tendency in cases of cystitis it is customary to 
wash out the bladder with a saturated solution of boric acid or 
some other unirritating antiferment. 

Preservative Fluid. — The sample of urine should be ex- 
amined within twelve hours after micturition, and preferably 
within three hours, merely allowing time for the deposit to settle. 
When it is desired to preserve a specimen for several days, it 
suffices to add 5 drops of chloroform or 10 gr. of thymol to 1 fl. oz., 



THE URINE 579 

or salicylic acid, about 3 gr. to \ pt. of urine. This will not pre- 
vent the changes of structure which sometimes take place in blood- 
cells, tube-casts, and renal epithelium when the urine is of low 
density. To protect these from alteration the density must be 
raised by adding some mineral salt, such as potassium acetate, 
in saturated filtered solution containing a few grains of salicylic 
acid. A sediment can be preserved indefinitely by first giving it 
several washings in a solution of chloral, 15 gr. to 1 fl. oz. of 
water, and finally setting aside, covered with the same solution. 
The chloralized specimen can be mounted permanently for the 
microscope. Chloral and chloroform each reduces Fehling's 
solution, and neither should be used if the urine is to be tested for 
glucose. For saccharine urine thymol is preferred, as it has no 
reducing action. Boric acid is a good preservative, in the pro- 
portion of 5 gr. to 4 fl. oz. of urine. Formaldehyd, 1 drop, will 
preserve a pint of urine one week, but it coagulates albumin if 
care is not observed, and it reduces Fehling's solution. 

Another method of preserving organized sediments is to wash 
three times with normal salt solution, and, after decanting, put 
the sediment in equal parts of glycerin and water with 2 per cent, 
of saturated alcoholic solution of thymol. 

Normal Urine. — The urine of health is a clear solution in 
water of various substances. Some of these impart a freely acid 
reaction; some give it a yellowish color; some are the source of 
its characteristic odor; and all combined raise its specific gravity 
to a point between 1015 and 1025. The proportion of its constitu- 
ents are not constant for all individuals, nor even for the same 
person taking one day with another; indeed, they vary hourly. 
In making a statement of average composition, regard is had to 
this variable character: the figures which follow may be taken as 
representing the average amounts in round numbers. 

. ... . . Percentage Grains Grams 

Average composition of normal urine. Composition. per diem. per diem. 

Water 96.0 50 fl. oz. 1200 c.c. 

Solids as tabulated below 4-° 1000 gr. 60 gm. 

Urea 2.000 500 30.00 

Uric acid 0.040 10 .65 

Hippuric acid 0.075 15 .95 

Creatinin 0.075 15 .95 

Pigment, mucus, xanthin, other ex- 
tractives, etc 1. 000 170 10.00 

Chlorids of potassium and sodium . 1. 000 1 70 10.00 

Sulphates of potassium and calcium . o. no 40 2.60 

Phosphates of potassium and sodium 1. 120 45 2.90 

Phosphates of magnesium and calcium 0.180 30 1.95 

Besides these, there have been found traces of indican, phenol, and other 
aromatic sulphates, diastase, oxalic, and lactic acids, unoxidized sulphur, and phos- 
phorus. 



5 8o 



FOODS AND DIGESTION 



C.C 



JM 






The Quantity. — In making a quantitative determination of 
any constituent, not only must the tested sample be a portion 
taken from the total mixed urine of the day, but the daily quan- 
tity of the urine itself must be known. The large 
collecting-jar may be graduated so as to be the 
measuring vessel: such wide-mouthed graduated 
jars as are used by druggists for percolating will 
serve admirably, though the common glass specie jar 
is about as good, and is easily obtained anywhere. 
It must be large enough to hold the entire daily 
discharge, and then for measuring the volume a 
smaller apothecary's graduated glass can be used. 
The wide mouth admits of the introduction of the 
hand for the thorough washing always required 
before beginning the daily collection. The patient 
is instructed to empty his bladder at a given hour, 
but not into the jar. Afterward, for twenty-four 
hours, the urine is passed into the one jar, which 
should be kept in a cool place, and at the given 
hour the last contents of the bladder are added to 
it. The amount should then be noted, and about 8 
fluidounces put into a perfectly clean glass bottle 
or other vessel to serve as a sample for analysis. 
Practical Import. — The mean daily discharge is 
1250 c.c, or 50 fl. oz., or 3 pints. In drawing con- 
clusions from any change in this respect, it is neces- 
sary first to note that even in health there may be 
considerable variation. The amount voided will depend, first, 
upon the amount of water drunk; it will be affected by the pro- 
portion of water lost in perspiration and the quantity retained 
in the tissues as necessary for nutrition. These factors are various 
in different men, and change with the season and with the habit 
of exercise. It is compatible with health in some for the daily 
discharge to reach only ij pints, and at times for it to go as high 
as 4 pints. Making allowances for these physiologic variations, 
the urine is notably scanty in certain forms of Bright's disease, 
in cirrhosis of the liver, and in the state of collapse occurring 
in cholera or the pernicious fever. 

By anuria is meant a condition in which the urine is no longer 
voided: this includes suppression, when the secretion of the kid- 
ney is suspended, and retention, when the fluid, although secreted, 
is retained in the urinary passages by mechanical obstruction. 
Oliguria is the term applied to urine scanty from low pressure of 
the blood or other cause. 

A persistent excess of the aqueous constituent, without a cor- 



Fig. 95. — Per- 
centage tube. 



THE URINE 581 

responding increase of the solids, is termed hydruria. This 
symptom is characteristic of diabetes insipidus, in which disease the 
daily discharge may be more than 8000 c.c, or 2 gal., while the 
specific gravity sinks to 1003 or less. Some diuresis occurs in 
the middle period of atrophic nephritis. Hysteric and neurotic 
subjects may suffer temporarily from a too copious urinary flow. 

By polyuria is meant an excess not only of urinary water, but 
of all the solid constituents. Beside the saccharine diabetes, 
it would include cases of azoturia, in which the urea is morbidly 
abundant, and the phosphatic diabetes of Teissier, which accom- 
panies an excessive tissue-waste. 

The Color. — Normal urine is amber-hued, the depth of color 
varying as the proportion of coloring-matter varies. When the 
volume of urine is low, the liquid is dense and the color deepens 
to a reddish tint. After liberal drinking, followed by copious 
urination, it may be almost as colorless as water itself. 

Beside its true coloring principles — urobilin, urochrome, 
hematoporphyrin, and uro-erythrin — the urine contains sulph- 
indoxylate of potassium or indican (KC 8 H 6 NS0 4 ), a colorless 
substance which forms indigo-red or indigo-blue by the action of 
reagents. 1 Its presence may be shown by Jaffe's test for indican: 
add to two inches of urine in a test-tube an equal volume of 
fuming yellow hydrochloric acid and one or two drops of liquor 
sodae chlorinatae or three drops of solution of hydrogen dioxid, 
or (the author's modification) a piece of sodium perborate (Sche- 
ring) as big as a pea. There is danger of carrying oxidation too 
far, changing the indigo-blue to yellow isotin. The sodium per- 
borate is less likely to do this than the chlorinated soda or chlori- 
nated lime. It is very stable in all climates and always ready for 
use, which can not be said of either of the chlorinated preparations 
or the hydrogen dioxid. On standing, the mixture turns bluish 
from the formation of indigo. The color may be concentrated 
by gently shaking with 1 c.c. of chloroform or of ether for two 
minutes; the indigo is taken up by it and on standing separates 
as a layer which is blue in color in proportion to the amount of 
indican. (Plate 8, Fig. 8.) With normal urine there is a pale 
blue color. Diseases of the liver and bowels which cause con- 
stipation thereby favor the absorption of indol from the fecal 
mass, and an increase of its derivative, indican, in the urine. 
This increase is revealed by the deeper color yielded when the 
above test is applied. A fallacy results if iodids are present 
through ingestion, as the free iodin dissolved in chloroform gives 

1 Artificial indicanuria can be made by adding to normal urine horses' urine, or 
an alcohol extract of its solid residue. The urine of the horse, rich in indican, can 
be kept ready for use by adding to it chloroform, five drops to the fluidounce. 



582 FOODS AND DIGESTION 

a rose violet color. Iodin in the ether layer would be brown 
and at the surface (p. 145). 

The urine is pale yellow in the free flow of diabetes and after 
attacks of hysteria or epilepsy; orange red from the elimination 
of santonin in an alkaline medium; reddish naturally after full 
meals with small potations, after severe exercise with abundant 
sweating, during paroxysms of fever, after hemorrhage into the 
genito-urinary tract, and, lastly, after the administration of log- 
wood; brownish from the condition known as melanosis, from 
hemoglobinuria, and from the administration of tar, carbolic acid, 
gallic acid, tannic acid, senna, trional, or sulphonal. Eating of 
blue candies and the administration of methylene-blue for gonorrhea 
will cause green urine. In jaundice the biliary coloring-matter 
(q. v.) will make it sulphur yellow or olive-green. 

Practical Import. — It is plain that excess of indican would 
point to diseases retarding digestion or causing constipation, 
though it has been found in cholera and all forms of severe cachexia. 
The detection of foreign coloring-matter would furnish indications 
of an obvious character based upon the nature of the specific 
substance: for that of blood consult the section on Hematuria; 
for that of bile, the section on Biliary Coloring Matter (p. 560). 

Urorosein is present as a chromogen in very small amount 
in normal urine. The amount is increased in advanced tubercu- 
lous disease, malignant diseases of the abdominal organs, typhoid 
fever, anemia, and diabetes. It changes to a rosy red pigment 
after the addition of an oxidizer, such as nitric acid, as a test for 
albumin. When the rosy tint spreads through the column of 
urine in Heller's test for albumin, an excess of urorosein is present. 
It can be distinguished from indigo-blue by its not separating 
after being shaken with chloroform. 

Alkaptonuria. — A peculiar dark-brown color has been observed 
in the urine of certain persons and certain families. It is attrib- 
uted to the presence of alkapton, which in the air oxidizes to a 
darker substance. In recent years cases have been reported which 
appear to be congenital. They could not be accounted for by 
special foods or medicines or diseases, the condition appearing to 
persist through life as an inherited anomaly of nutrition. The 
latest view is that the material of alkaptonuria is a substance 
called homogentisic acid or hydroquinone-acetic acid, C 6 H 3 (OH) 2 
CH 2 COOH, which is occasionally mixed with uroleucic acid. 
The urine containing them becomes dark-colored on exposure 
to the air and reduces Fehling's solution. Homogentisic acid is 
formed in the small intestine as a cleavage product of the protein 
molecule, but that found in the urine is due to a specific derange- 
ment of protein metabolism. 



THE URINE 



583 



Specific Gravity. — When it is desired to make use of this 
property in determining by special formulas the amount of urea 
or of sugar in solution, it is best to take the observation with a 
delicate Mohr balance or with the specific-gravity bottle. A bot- 
tle of known capacity, say of 1000 gr., is counterpoised, then 
filled with urine, and weighed in a delicate balance. If the con- 
tents weigh 1025, that number will be the specific gravity. This 
operation requires apparatus not always at hand, and consumes 
time not always at the disposal of the physician. For ordinary 
purposes it suffices to take the specific gravity with a urinometer, 
which is a spindle hydrometer for liquids heavier than water, car- 
rying a scale ranging from 1000 to 1060, and usually made to 
read at 15 ° C. (60 ° F.). When the sample of urine is too small 
in amount to use the urinometer, the specific gravity of 1 c.c. can 
be taken by the method described under the section on Specific 
Gravity (p. 25). 

Method. — Fill to one-half its capacity a cylindric vessel having 
a level lip. Gently immerse the urinometer and carefully fill the 
cylinder to the brim. Take the observation by sighting on a 
level with the surface of the urine, which rises slightly above the 
edge of the glass. Note the lower surface line and not the point 
to which the liquid is attracted up the side of the scale. 

Practical Import. — The standard of health is usually rated as 
between 1015 and 1025, but very free use of beverages may cause 
it to fall below 1010. Under ordi- 
nary conditions, in regard to the 
amount of fluid ingested, so low a 
density would point to diabetes sim- 
plex or to Bright's disease with defi- 
ciency of urea. When the record is 
above 1030, it usually denotes sugar 
in the urine. In either case the proper 
chemical tests would solve the doubt. 

Total Solids. — It is possible to 
derive valuable conclusions from 
roughly estimating the solid constit- 
uents of the urine by multiplying 
the last two figures of the specific 
gravity with Haeser's factor, 2.33. 
This gives parts of solids per thousand 

of urine, and after measuring the number of liters passed in 
twenty-four hours, furnishes some idea of the efficiency of the 
kidney at the time. Another rule giving grains of solids is to 
take the total number of fluidounces passed in the day, multiply 
by the two last figures of its specific gravity, and add 10 per cent. 




i 



Fig. 96. — Squibb's urinometer. 



584 FOODS AND DIGESTION 

Thus if 50 fl. oz. be passed, the specific gravity being 1015, the 
total solids are found by 50X15 = 750 and 750 + 75 = 825 grains. 
The average amount excreted daily by a healthy male is 70 gm., 
or 1 100 grains. 

Cryoscopy. — The determination of the freezing-point, lowering 
of the urine as evidence of the molecular concentration, is a help 
to which reference has been made in another place (p. 39). The 
method is invested with so many technical difficulties that the 
practical physician contents himself with deducing the activity 
of the kidneys in this respect empirically by multiplying the last 
two figures of specific gravity carried to the third decimal place, 
by factor 0.075 ° C. The sample must be free of sugar and 
albumin. Thus, if the specific gravity carefully taken gave the 
last two figures and decimal as 10.125, then 10.125X0.075 = 
0.759 C, which is less than the normal range (1.2 to 2.3). 

Reaction. — In noting the reaction blue and red litmus-papers 
may be used, but the most convenient indicator is violet-colored 
neutral litmus-paper. Acids turn it red and alkalis blue. A 
sample of the total daily urine of health should turn this neutral 
paper, or even the blue paper, to a delicate red. This shows an 
acid reaction due to the dissolved acid phosphates and perhaps 
urates. 

Occasionally a sample is encountered which turns blue litmus 
red and red litmus blue. It is said to have an amphoteric reac- 
tion^ due to the fact that the urine contains both the acid phos- 
phate NaH 2 P0 4 and the alkaline Na 2 HP0 4 . 

Test for Acidity. — Having measured into a beaker 100 c.c. of 
urine and put in it a strip of red litmus-paper, the sample is 
titrated with decinormal potassium or sodium hydroxid from a 
graduated buret. Acidity is expressed in terms of oxalic acid, of 
which 0.0063 gm. equals 1 c.c. of the decinormal potash solution. 
If 12 c.c. of the potash neutralize 100 c.c. of the urine, then the 
acidity of 100 c.c. is 12X0.0063=0.0756, which is the same as 
0.756 parts per thousand. Further details are given under 
Acidimetry (p. 124). 

Owing to the fact that the acidity of the urine is due to an 
acid salt which is imperfectly saturated by the testing alkaline 
solution, a difficulty arises which is not encountered in determining 
the acidity of simple acid liquids. Complex methods have been 
devised to overcome the difficulty, which are not free from error, 
and hence the ordinary titration given above is preferred as being 
easy, though the estimation usually figures too low. 

Sometimes in health a sample representing the unmixed urine 
secreted during the first or second hour after a full meal is alka- 
line or neutral, as an effect of the preponderance of alkaline salts 



THE URINE 585 

in the food. The paper made blue by such a sample retains the 
blue color, thus indicating fixed alkali — that is, alkaline salts of 
sodium and potassium. 

The same change can be produced at will by the repeated 
administration of large doses of the bicarbonates or citrates of 
sodium and potassium, as in the alkaline treatment of rheumatism. 
When the paper is turned blue by the volatile alkali ammonia, we 
may know it by the gradual restoration of the original color as 
the ammonia volatilizes. A characteristic putrid odor attends 
this reaction. It is due chiefly to the ammonia evolved from 
ammonium carbonate resulting from the decomposition of urea 
by the Micrococcus urea. 

CON 2 H 4 + 2(H 2 0) = (NH 4 ) 2 C0 3 

Urea. Water. Ammonium carbonate. 

Practical Import. — Persistent alkalinity due to fixed alkali is 
sometimes found in persons of a feeble habit of body. The 
change in reaction lessens the solvent power of urine for the 
earthy phosphates, which in consequence are precipitated in loose 
whitish amorphous particles. These do not tend to form concre- 
tions. If the alkalinity be due to ammonia, the indication is very 
different. The ammoniacal change occurring in the bladder is a 
concomitant of serious vesical mischief. The earthy phosphates 
are mixed in a deposit with the triple phosphates of ammonium 
and magnesium. If the bladder be not kept well washed of this 
deposit, it will in time accrete into the mixed phosphate gravel or 
calculus. In every case of incomplete evacuation of the bladder 
from paralysis or obstruction this is a rock ahead. 

It remains to be said that the administration of acids, unless it 
be benzoic acid, which is changed to hippuric acid, while tending 
to acidify the urine, will have little direct effect upon the reaction. 
The strongest acids, given in usual doses, are neutralized before 
they enter the circulation. Whatever power they have over the 
alkaline urine of feeble subjects is explained by the increased tone 
they impart to digestion, thus removing debility and anemia. 
Given by the mouth, they exert no control over ammoniacal urine. 

Urotropin is given to check the ammoniacal fermentation, which 
it does by liberating formaldehyd in the urinary passages. Doses 
of acid sodium phosphate (XaH 2 POJ given at the same time are 
eliminated by the kidneys and will lower the alkaline reaction by 
neutralizing the ammonia in the urine. 

Phosphates. — The urinary phosphates may be divided into 
two groups, earthy and alkaline, according to their bases. The 
'total daily discharge of these is about 60 gr. or 4 gm., the two 
phosphates of calcium and magnesium, or earthy (MgHP0 4 + 



PLATE 7. 
URINARY SEDIMENTS. 

The most important macroscopic varieties of urinary sedi- 
ment are represented in the three conical glasses. 

Fig. 1. Brick-dust Sediment.— This is formed only of t uric 
acid, and is found in abundance in febrile states, after active 
bodily exertion, etc. It dissolves on heating. 

Fig. 2. Yellowish Friable Sediment. — This may consist of 
phosphates (soluble on addition of acid), of pus-corpuscles, of 
renal elements, of bacteria (demonstrable microscopically). 

Fig. 3. Bloody Sediment.— Demonstrable by Heller's blood- 
test (see Plate 8, Fig. 10), as well as by microscopic examination 
(renal or vesical hemorrhage, hemoglobinuria). 

Uric=acid Sediment. 

Fig. 4. Sodium Urate, in small yellowish granules, frequently 
adherent to other elements, especially casts, etc. 

Fig. 5. Uric-acid Crystals, varying in color from yellow to 
yellowish-brown, in large, not entirely regular plates, in whet- 
stone, dumb-bell, and comb-like form and arrangement. 

Both sedim ents occur only in urine of acid reaction, and are 
precipitated by addition of acid. They dissolve upon addition 
of potassium hydroxid. 

(Jakob.) 



PLATE 7. 




THE URINE 587 

tion of sodium acetate containing an excess of acetic acid. Heat 
on a sand-bath or wire gauze until boiling begins, and then from 
a buret slowly add about 2 c.c. of standard solution of uranium 
acetate, causing a precipitate of uranium phosphate. Stir with a 
glass rod, and touch its wet end to a drop of solution of potas- 
sium ferrocyanid on a white plate. A red-brown color indicates 
that too much standard solution has been used, and the process 
must be repeated. However, this is not likely when only 2 c.c. 
have been used. If no red-brown spot appear, continue to add 
from buret slowly, and after the addition of each 1 c.c. stir and 
touch the rod to the ferrocyanid. When the red-brown spot 
appears, read off the number of cubic centimeters taken from the 
buret. The standard solution contained 31.1 gm. of uranium 
acetate to 1000 c.c. of water, equal to 5 gm. of phosphoric acid 
(P 2 5 ). If 1000 c.c. = 5 gm. P 2 5 , then 1 c.c. will represent 
0.005 gm. P 2 0- in the 50 c.c. of urine employed. The terms in 
percentage can be obtained by multiplying the number of cubic 
centimeters used by 0.01, which is the equivalent of 0.005X2. 
To get grains to the fluidounce multiply the per cent, by 4.55. 

Practical Import. — When it is considered that the phosphates 
of the urine are derived only in part from the waste of nervous 
tissue, part being supplied by the rest of the body, and an uncer- 
tain amount coming almost directly from the same principles in 
food, it will be easily understood why the quantitative estimates 
so far have proved of no direct value to the clinician. Their sig- 
nificance depends not on the relative proportion in the sample, 
but upon their state. Any amount, large or small, in an undis- 
solved state will figure as a deposit, and thereby have pathologic 
meaning (PL 7, Fig. 2). 

Phosphatic Deposits. — It has been said above that the phos- 
phates of normal acid urine are held in clear solution. When 
the urine is alkaline, it loses its solvent powers for the earthy 
phosphates, and throws them down as a grayish-white sediment 
made of colorless granules, which show no tendency to aggregate 
into masses having particular shapes. The amorphous urates 
form into groups which branch somewhat like sprigs of moss. 
A drop of acetic acid insinuated under the cover-glass will clear 
away the phosphates, but not the urates. If the alkalinity be due 
to the ammoniacal fermentation of urea, then the ammonia reacts 
with the magnesium phosphate to produce the white crystalline 
deposit of ammoniomagnesium phosphate — the so-called triple 
phosphate. 

2 MgHP0 4 + (NHJ 2 C0 3 = H 2 CO s + 2 MgNH 4 P0 4 

Magnesium phosphate. Triple phosphate. 



5 88 



FOODS AND DIGESTION 



Usually the crystals are large enough to be seen by the naked 
eye as minute glittering points, which the microscope resolves 
into large, bright triangular prisms or modified forms, sometimes 
feathery and sometimes having a resemblance to a coffin-lid (see 
Fig. 97). 

The existence of these mixed phosphates as a spontaneous 
deposit at the time of micturition usually indicates some serious 
bladder trouble, such as cystitis or paralysis or stone. Incom- 
plete evacuation of the bladder has favored the ammoniacal fer- 
mentation in the retained urine. If the condition persist, there 
is ground to fear that eventually a phosphatic concretion will form 
in the bladder and in the pelvis of the' kidney. 

Stellar calcium phosphate is sometimes deposited in urine which 
is alkaline from fixed alkali, and is rarely seen except in some 




Fig. 07. — Triple phosphate and spheres of ammonium urate. 

general disorder of serious import. Commonly it occurs in arrow- 
heads or slender wedges, singly or gathered in star-like masses 
(see Fig. 98). 

Sulphates. — Sulphuric acid is present in the urine partly as 
preformed mineral sulphates, and partly as compounds conjugated 
with phenol, indol, and skatol, known as ethereal or aromatic sul- 
phates (p. 430). The sulphates of the alkaline metals and mag- 
nesium (K 2 S0 4 + Na 2 S0 4 +MgS0 4 ), which are eliminated by the 
urine to the extent of about 2 gm. or 30 gr. daily, are derived chiefly 
from the diet and partly from the oxidation of the protein principles 
of the tissues and fluids. 

These mineral salts make up nine-tenths of the total sulphates; 
the remaining one-tenth is in the form of ethereal compounds of con- 
jugate acids, such as the phenol-, cresol-, indoxyl-, and skatoxyl- 



THE URINE 



589 



sulphates of potassium. These are products of protein putre- 
faction, absorbed from the intestines and eliminated by the kidney. 
Their normal amount varies between 0.12 and 0.3 gm. Any in- 
crease is roughly indicative of intestinal indigestion (p. 581). 

Determination of Total Sulphates. — Mix urine, 100 c.c, with 
20 c.c. of 5 per cent, barium chlorid and 10 c.c. of hydrochloric 
acid. Boil half an hour; filter the white precipitate of barium 
sulphate; collect, dry, and weigh. For 100 parts of the BaS0 4 
calculate 42 parts of absolute H 2 S0 4 , or 34.3 parts of sulphuric 
anhydrid, SO s . 

Determination of Ethereal Sulphates Only. — These can be 
determined by the following procedure: Take of urine 200 c.c. and 
mix with an equal volume of barium chlorid made alkaline with 
barium hydrate. Filter off the precipitate through dry paper. 




Fig. 98. — Stellar calcium phosphate. 

The clear filtrate contains the ethereal sulphates, which are not 
precipitable by barium chlorid until they are decomposed by boiling 
with hydrochloric acid. Take 200 c.c. of this filtrate, representing 
100 c.c. of urine and 20 c.c. of hydrochloric acid, and boil ten 
minutes. Filter, dry the precipitate, and calculate H 2 S0 4 as stated 
above. The easiest clinical test is the one known as Jajje's test 
for indican (see Indican, p. 581). In general the indican reaction 
is deep in color in proportion to the total excretion of ethereal sul- 
phates (p. 487). 

Centrifuge Estimation of Mineral Sulphates. — Into the 
graduated tube put 10 c.c. of urine and 5 c.c. of barium chlorid 
solution (BaCl 2 , 4 parts; HC1, 1 part; H 2 0, 16 parts). Invert 
several times, set aside for three minutes, and rotate three minutes. 
Read each yV c.c. of sediment as percentage by bulk, the normal 



59° 



FOODS AND DIGESTION 



amount being 0.8 per cent. Every yV c.c. of sediment represents 
0.25 per cent, of S0 3 , or 1.1 gr. to 1 fl. oz. 

Practical Import. — Although their amount is increased by fever 
and other wasting pathologic conditions, the increase is not strictly 
proportional. The effect of diet is not easily calculated, nor can 
exact allowance be made for the uneven action of the eliminative 
process. On these accounts it is of little value to the clinician to 
determine the amount of the mineral sulphates. When the blue 
indican reaction is strong, it shows that the ethereal sulphates are 
increased, and we find, at the same time, symptoms of impaired 
intestinal digestion, such as pains, flatulence, constipation. Before 
operation for cancer of the intestines it is desirable to know if the 
intestines are empty. This is indicated by the decline of conjugate 
sulphates in the urine to a mere trace. 

Chlorids. — Nearly 200 gr., or 8 to 12 gm., of these salts (NaCl 
and KC1) are discharged daily by the urine. They are greater 
in amount than the sulphates and phosphates together. In testing 
for them the sample is first acidulated with a few drops of nitric 
acid, so as to hold the phosphates in solution. Then, drop by drop, 
a strong solution of silver nitrate (3j-f^j) is added so long as white 
curds of silver chlorid are precipitated. If the amount of chlorids 
is less than normal, then, instead of heavy curds being formed, the 
urine becomes milky or cloudy. A rough estimate can thus be 
made as to any marked deviations from the normal quantity. To 
make a volumetric determination put 10 c.c. of urine into a beaker 
and add 50 c.c. of water and 8 to 10 drops of neutral potassium 
chromate. From a buret let fall by drops the standard solution of 
silver nitrate while stirring with a glass rod. As soon as the urine 
in the beaker becomes permanently orange red throughout, read 
off the cubic centimeters used, subtracting 1 c.c. for excess of 
silver solution. 

As the standard solution contained of AgNO s 29.06 gm. per 
1000,, equal to 10 gm. NaCl, so 1 c.c. = 0.01 NaCl in the 10 c.c. 
used, or 0.1 per cent. To get the percentage of chlorids mul- 
tiply the number of cubic centimeters noted by 10; to get the 
number of grains to the fluidounce multiply the cubic centimeters 
by 45.57. Thus, if 13 c.c. were used, 12 c.c. would be counted. 
If 1 c.c. = 0.01 NaCl, then 12 = 0.12, or 1.2 per cent. While this 
method may be considered sufficiently accurate for clinical pur- 
poses, it fails in exactness when the urine is high-colored, albumin- 
ous, or putrid. 

The centrifuge determination by volume is made with urine 
previously filtered or rotated until clear. The clear urine to the 
amount of 10 c.c. is put into the percentage tube, then acidulated 
with 1 c.c. of nitric acid, and finally 4 c.c. of strong solution of 



THE URINE 591 

silver nitrate is added (3j-foj). Stand aside three minutes after 
several inversions. After rotating for three minutes the precipi- 
tated chlorids are read oft* as 1 per cent, by bulk for every tV c.c. 
The measure of normal chlorids is from 10 to 12 per cent. 

Every yV c.c. represents 0.13 per cent, of NaCl by weight, or 
0.62 gr. to 1 fl. oz. The normal proportion of NaCl by weight is 
1 per cent. 

Practical Import. — It has been observed that in acute febrile 
diseases, such as pneumonia, pleurisy, and rheumatism, at the 
stage in which exudations are forming, the chlorids are retained 
in the body while they diminish in the urine. In cases of pneu- 
monia with extensive exudation they may totally disappear. Their 
reappearance may be expected when resolution sets in and the 
fever declines. The missing quantity is made up by excess in 
convalescence. 




Fig. 99. — Calcium oxalate. 

Calcium Oxalate. — While oxalic acid is usually stated to be a. 
constituent of the urine, the amount should not exceed what is 
called a trace. Its combination with calcium is soluble to such an 
extremely small amount by the aid of the acid phosphates that 
anything more than a trace appears as a spontaneous deposit. Its 
naked-eye characters are not distinctive from those of mucus or 
epithelial debris. Its crystals are very minute, and call for the 
microscope to make out their form. It takes two different shapes, 
more commonly occurring as octahedra, which appear as bright 
squares with diagonal cross-lines, like envelops, and sometimes, 
though rarely, showing as very small dumb-bells, or forms re- 
sembling an hour-glass (see Fig. 99). 

Practical Import. — It is probable that a diet of subacid fruits 
and vegetables, like rhubarb or pie-plant, containing oxalates will 



592 



FOODS AND DIGESTION 



furnish directly oxalic acid to the urine. As it is a laboratory 
product of oxidation changes in fats, sugars, and starches, it is 
easy to see why impaired digestion or retarded metabolism may 
be the source. Although appearing sometimes without assign- 
able cause, it usually attends conditions to be remedied by plain 
diet, temperance, and outdoor life. It is frequently incidental to 
the gouty habit. The deposit may be transient, scanty, and un- 
important, or it may be persistent and more abundant, and on 
these accounts serious, as indicating a disposition to the formation 
of a concretion of the kind known as the mulberry calculus. These 
calculi are so rough as to cause frequent bleeding in the bladder, 
the blood imparting a dark color. 

Urea. — As it is the chief solid constituent of the urine, urea is 
also the most important physiologically as well as pathologically. 
Its chemical formula, CO(NH 2 ) 2 , shows its nitrogenous character, 
and presents the view held as to its nature, a carbonyl diamid 
(p. 193). The amount excreted daily is nearly 500 gr., or 40 gm., 
equal to all the other solids put together; from which it will be 
seen what a conspicuous role is played by it as a compound rep- 
resenting the waste of the protein or nitrogenized principles. 
Neutral in reaction, freely soluble in water and alcohol, though 
insoluble in ether, it is without color or odor, but has a bitter taste. 
In its chemical behavior, while it does not affect litmus, at times 
it is basic, and then again it may act in a compound, as acids do. 
From concentrated solutions it can be crystallized slowly in quad- 
ratic prisms beveled at the ends (pp. 200, 492). 

If the urine be evaporated in a water-bath to the consistence 
of syrup and nitric acid added to it, the crystals of urea nitrate 
should soon form in rhombic plates or hexagonal scales. Failure 
to precipitate crystals under these conditions (when the urine has 
been evaporated one-half) would indicate deficiency in the pro- 
portion of urea in the sample. 

Urea is decomposed by boiling the urine; by the action of fuming 
nitric acid; by free chlorin or bromin, or certain of their compounds, 
such as sodium hypochlorite and hypobromite: 

N 2 H 4 CO + 3NaBrO = 3NaBr + 2H 2 + 2N + C0 2 . 

Urea. Sodium hypobromite. 

The above equation represents the reaction of urea with sodium 
hypobromite. As stated, it yields sodium bromid, water, free nitro- 
gen, and carbon dioxid. By using with the sodium hypobromite 
an excess. of alkali, such as sodium hydroxid, as in Knop's fluid, the 
C0 2 is fixed in the solution as carbonate, and the only gas escap- 
ing is free nitrogen. The equation for this reaction is as follows: 

N 2 H 4 CO + 3 NaBrO + 2NaHO = 3NaBr + Na 2 C0 3 + 4H 2 + N 2 . 



THE URINE 593 

Hypobromite Method. — Different forms of apparatus have 
been devised to measure the free nitrogen evolved by the sodium hy- 
pobromite. The form usually employed is known as Russell and 
West's or as Apjohri's. The urine and the reagent are mixed 
and the effervescing gas is delivered by a rubber tube at the top 
of a graduated cylinder open at the bottom and immersed in 
water serving as a gasometer. This collecting cylinder may be 
graduated in cubic centimeters, and in such a case the determina- 
tion will be made on the basis of i c.c. of nitrogen evolved for 
0.0027 g m - °f urea. Sometimes it is graduated to read percent- 
age, on the principle that 5 c.c. of a 2 per cent, solution of urea 
will yield 37.1 c.c. of nitrogen. As solutions of sodium hypobro- 
mite are unstable, in order to insure an accurate result it is best 
to prepare them freshly, according to the formula of Knop, and if 
any great interval must elapse between successive determinations, 
it is best to keep the reagent in two parts, each of which is stable. 
Knop's solution is made by dissolving 100 gm. of sodium hydroxid 
in 250 c.c. of water. This should be kept in a separate bottle, 
with a stopper of rubber or of glass coated with paraffin. When 
the fluid is to be used, measure out 15 c.c, and mix with it 1 c.c. 
of bromin. Care must be observed in pouring the bromin, as 
the vapor is highly irritating to the eyes and air-passages. 

Squibb 7 s Fluids. — Squibb uses two fluids, one (a) a solution of 
sodium hydroxid, 100 gm. in 250 c.c. of water; the other (b) a 
solution of bromin and potassium bromid, made as follows: 
Weigh the contents of a i-ounce bottle of bromin by deducting the 
weight of the bottle empty from the weight when filled. Pour 
the bromin into a bottle of 300 c.c. or 10 fl. oz. capacity. Add to 
the bromin an equal weight of potassium bromid and as many 
cubic centimeters of water as eight times the number of grams of 
bromin. When used, mix (a) and (b) in equal parts. 

The procedure is as follows: First, immerse the graduated 
gasometer tube upright until the water rises in it to the zero mark. 
Measure the 16 c.c. of Knop's fluid into the flask, and then, by 
means of forceps or a string (to hold it upright, so as not to spill), 
put in a short test-tube containing 5 c.c. of urine. Close the flask 
tightly with a rubber stopper carrying a gas-tight rubber connection 
with the graduated gasometer. Now tip the flask so as to gradually 
pour out the urine into the surrounding hypobromite. By perform- 
ing this slowly there is greater certainty that the C0 2 will be held 
fixed by the alkali, and that nitrogen only shall pass into the meas- 
uring vessel. After waiting ten minutes to complete the decompo- 
sition of urea, raise the gasometer so that the water within is on a 
level with that outside, and read off the cubic centimeter of nitrogen 
collected (or the percentage of urea if the tube be so graduated). 
38 



594 FOODS AND DIGESTION 

The computation is 0.0027 °f urea in the 5 c.c. of urine used 
for each cubic centimeter of nitrogen. Thus, if the gasometer 
records 7 c.c. of nitrogen, then there were 7X0.0027 = 0.0189 
gm. of urea in the 5 c.c. of urine. Multiplying by 20 to get the 
percentage, we have 0.0378 per cent. 

To calculate grains to the fluidounce, multiply the percentage 
by 4.55. If the apparatus be stated to have been graduated at 
65 ° or 70 F., reasonable accuracy in results can be obtained 
be taking the observation in an apartment at or near that temper- 
ature. The variation of temperature indoors would then affect 
the volume of gas so little as to be of small moment in clinical 
observations. In such cases differences of barometric pressure 
might be ignored without seriously affecting the calculation. 1 

Hinds-Doremus Ureometer. — A form of apparatus was devised 
by W. H. Greene, which consisted of a single tube for the reaction 
and the measurement of nitrogen. The most convenient modifi- 
cation of Greene's idea is that known as the Hinds-Doremus 
ureometer (Fig. 100). It consists of a bulb with an upright tube 
(a) graduated so that each of the smallest divisions represents 
0.001 gm. of urea in the urine used. Connected with the lower 
portion of the tube is a ground-glass stop-cock (b) which sup- 
ports a smaller upright tube (c) graduated with a capacity of 
2 c.c. Closing the cock (b), the bulb is filled with Knop's or 
Squibb's fluid diluted one-half (see p. 594), or liquor sodce chlo- 
rinate. The opening is then closed with the thumb and the tube 
inverted so as to fill with the reagent. When restored to an up- 
right position, the smaller tube (c) is filled to the zero mark with 
urine. The cock (b) is turned slowly, so as to admit gradually 
1 c.c. of the urine to the measuring tube (a). In about fifteen 
minutes the gas nitrogen ceases to collect at the top of the tube 
and the level may be read off as so many grams of urea in the 1 
or 2 c.c. of urine used. 

If the reading was 0.015 an d the amount of urine used was 
1 c.c, then multiplying by 100 gives 1.5 per cent, of urea. A 
more correct reading is obtained by submerging the whole appa- 
ratus in a pitcher or beaker until the water outside and the hypc- 

1 Some gas-measuring tubes are graduated to be read at a temperature of o° C. 
(32 F.) and barometric pressure of 30 in. or 760 mm. 

Owing to the susceptibility of gas-volumes to variations of heat and pressure, to 
ensure perfect accuracy, a correction must be made according to the following 
formula : 

V = F ^-^ , in which 

760 (1+0.003667") 

V' = volume required ; V= volume observed ; 

b = barometer in mm. ; w = tension of aqueous vapor ; 

T = observed temperature, Centigrade. 



THE URINE 



595 



bromite inside are on a level. As the instrument is graduated 
experimentally at 19 ° C. (65 ° F.), no correction is usually neces- 
sary for temperature. Ordinary variations of atmospheric pres- 
sure may be ignored when the results are intended for clinical use. 
Immediately after using, the tube should be washed with alcohol. 

Although sufficiently accurate for clinical purposes, the hypo- 
bromite process liberates only 93 per cent, of the urea nitrogen, 
part of the deficiency being made up from the creatinin, hippuric 
acid, and the purin bodies. For exact studies these other nitrog- 
enous substances are first removed by the Morner process of 
precipitation, by adding a mixture of barium chlorid and hydrate 
to the urine along with ether and alco- 
hol. The filtrate of ether-alcohol hold- 
ing urea in solution is concentrated by 
heat to get rid of ammonia, and is then 
submitted to the Kjeldahl process for 
determining nitrogen (p. 365). 

Practical Import. — Urea being freely 
soluble never figures as a spontaneous 
urinary deposit. Morbid conditions 
causing increased tissue waste will al- 
ways run up the proportion of this prod- 
uct. In fevers and divers inflamma- 
tions the amount is increased in the 
early, or forming, stage and then de- 
clines with the febrile movement. In 
all acute diseases, as well as in phthisis, 
the rate of excretion rises and falls with 
the exacerbations of fever. In acute yellow atrophy of the liver at 
first it may be increased, but soon it declines notably, and in the end 
may disappear utterly. There is apt to be a marked lessening in 
the proportion when acute or chronic Bright's disease affects the 
eliminating powers of the kidney. Eventually this brings on the 
very dangerous symptoms of uremia. When urine is retained in 
the bladder from diseases which interfere with complete evacuation, 
the ready conversion of urea, which is locally innocuous, into irritat- 
ing ammonium carbonate causes it to figure as a pathologic factor. 

Uric Acid. — The chemical formula of uric acid, C 5 H 4 N 4 3 , 
shows its derivation from the nitrogenous principles of the body. 

Its structural formula (p. 488) as a trioxypurin shows that it is 
formed through oxidation of purin groups. Much of it is changed 
to urea in the liver, kidneys, and muscular tissue, but some is elimi- 
nated in the urine. While it resembles urea in containing nitrogen 
and in its origin, it is very unlike it in other respects. The average 
daily quantity excreted is only 10 gr. or 0.7 gm. Taking 40,000 




Fig. 100. — Hinds' modification of the 
Doremus ureometer. 



596 



FOODS AND DIGESTION 




parts of water for its solution, it may be considered as practically 
insoluble in that medium, though dissolving in iooo parts of blood- 
serum and freely soluble in the alkalis and 
solutions of the alkaline carbonates. A trace 
of the free acid may be discovered in normal 
urine, but anything more than a mere trace will 
be precipitated, and then it has pathologic 
significance. The 10 gr. eliminated daily are 
not free, but combined with sodium and potas- 
sium as urates, soluble at ordinary temperatures 
by the help of the alkaline phosphates, which 
prevent decomposition by the acid salts of the 
urine. A dense urine kept long enough to pass 
into the acid fermentation will throw out the 
uric acid along with acid sodium urate and 
calcium oxalate. The acid can be separated 
from its bases artificially by adding 10 parts 
of hydrochloric acid to ioo of urine. After 
standing forty-eight hours minute brown crys- 
tals of uric acid will fall. To collect these, and 
thereby obtain an approximate estimate of the 
amount, the supernatant urine should be de- 
canted, the sediment washed by stirring it with 
30 parts of water, and then collected by throw- 
ing them with the water upon a weighed filter. 
After drying the filter with its sediment in a 
hot-air chamber it can be weighed again, and 
then, allowing for the weight of the paper, the 
weight of the crystals can be ascertained. 

Ruhemann's Uricometer for the Rapid 
Estimation of Uric Acid. — This test is based 
on the principle that a brown iodin solution is 
neutralized by a certain proportion of uric acid 
until the brown color vanishes completely. Its 
author has calculated the exact amount of iodin 
and potassium iodid necessary to determine the 
percentage of uric acid in a given amount of 
urine, and on that basis has constructed a 
graduated scale. 

Fill the dry glass tube shown in diagram 
(Fig. 101) to the lowest mark S with carbon bi- 
sulphid. The lowest part of the convexity 
(double meniscus) has to be even with mark 



Fig. 10 i. — Ruhemann's 
uricometer. 



gr. potassium 



5. 
iodid, 



A solution consisting of 1.5 gr. iodin, 1.5 



*5 



gr. absolute 



alcohol, and 185 gr. dis- 



THE URINE 597 

tilled water is added as much as will fill up to the mark /, as 
shown in the illustration. Then add the urine to the mark 
2.45 (2.6 c.c). Close the tube with the glass stopper and 
shake well, when the carbon bisulphid will become of a dark 
copper-brown color. After adding more urine under continued 
shaking the carbon bisulphid will absorb all free iodin . and the 
mixture will look like urine. Slowly adding more urine will change 
the yellow foam, created by shaking, into white foam. The color 
of the carbon bisulphid will turn pink after a while. Should this 
color remain the same after the apparatus has been reversed and 
shaken repeatedly, add another drop of urine and keep on adding 
and shaking until only a slightly reddish coloration of the carbon 
bisulphid remains. Now shake again vigorously, and the carbon 
bisulphid will turn porcelain white, and the urine will look like 
cloudy whey. 

Precaution. — Stop adding urine as soon as the carbon bisul- 
phid shows only a slightly reddish tint, because this will disappear 
entirely after repeated shakings. The test is finished when the 
indicator appears snow-white, a sign that all iodin has been neu- 
tralized by the urine. 

To get rid of the remaining foam move the tube a few times 
slowly to a horizontal position, then open the stopper a little, to 
allow all liquid to settle in the tube. The proportion of uric acid 
is then read off at the surface of the fluid as parts per thousand. 

If the upper meniscus line of the urine be between any of the 
0.1 c.cm. marks, the upper number should be read. Should the 
urine contain less uric acid than the apparatus will in this manner 
indicate, add the iodin solution to the mark halfway between S and 
/, and read after reaction the half-values. If the urine show an 
acid reaction, it can be used at once; but if it be alkaline, it must be 
made acid by a drop of acetic acid. Cloudiness is of no importance. 
If the urine contain a considerable sediment of sodium urate, it 
should be well shaken. Strong colorations of the urine do not 
affect the action of carbon bisulphid. Traces of sugar and albumin 
do not disturb the result, but if there be a very large percentage of 
albumin or traces of blood or pus, these pathologic substances 
have to be coagulated by boiling and the urine filtered. 

The Hopkins modified method of uric acid estimation is a 
simple and accurate process based upon the fact that ammonium 
chlorid precipitates uric acid from the urine as ammonium urates. 

In a beaker over gauze warm 150 c.c. of urine (made neutral 
in reaction) to 40 or 45 ° C. and dissolve in it 30 gm. of ammo- 
nium chlorid. After standing one hour the precipitate is collected 
on a filter and washed with a 10 per cent, solution of ammonium 
sulphate. 



598 FOODS AND DIGESTION 

The precipitate is then washed off the filter with 100 c.c. of 
hot water into a beaker, 15 c.c. of concentrated sulphuric acid are 
added, and the whole is titrated with N/20 potassium permanganate 
solution (1.6 gm. in 1000 c.c). The end of the operation is 
reached when a slight permanent red tinge first appears. One 
c.c. of N/20 potassium permanganate solution corresponds to 
0.00375 gm. of uric acid in the 150 c.c. used. 

The centrifuge method of estimating requires that the phos- 
phates be first separated by placing 10 c.c. of urine in the per- 
centage tube with about 1 gm. of sodium carbonate and 1 to 2 c.c. 
of ammonium hydrate. The phosphate precipitate is thrown 
down by rotation, and the clear urine poured off into another 
tube. To this is added 2 c.c. of ammonium hydrate and 2 c.c. of 
a 5 per cent, solution of silver nitrate (to which ammonium hy- 
drate has been added until the first precipitate clears up); and the 
translucent precipitate of silver urate is separated by rotation. 
Having poured off the clear liquid, the precipitate of silver urate 
is washed free of chlorid by mixing it with at least 5 c.c. of ammo- 
nium hydrate. The mixture is then well rotated until the precipi- 
tate is reduced to its least bulk. For yV c.c. of this precipitate the 
uric acid is read off as 0.001176 gm. in 10 c.c. of urine. To get 
percentage this product is again multiplied by 10. Thus: if the 
reading was 0.5, then 5X0.00176 = 0.00588 gm. in 10 c.c. or 0.0588 
per cent. 

Murexid Reaction. — Uric acid, free or in combination, can be 
identified by the murexid reaction. To obtain this the suspected 
substance is treated in a watch crystal or porcelain dish. After 
adding a few drops of strong nitric acid, enough to dissolve, a slow 
heat is applied to evaporate the solution to dryness. A yellow or 
reddish residue is obtained. This, touched with a drop of aqua 
ammonia or held over the open mouth of the bottle of ammonia, 
should turn to a bright crimson, purple, or violet (murexid) 
(p. 489). 

If the crystals of uric acid be examined under a microscope, 
they are found to be of a pointed oval form. As they fall they 
take up the coloring-matter of the urine, which makes them red or 
brownish. 

When the crystals fall spontaneously they are larger, though 
still minute, and can be made out by the naked eye as the only 
brown specks of this size found in the urine. They are not unlike 
grains of red sand or ground cayenne pepper. Under the micro- 
scope they appear as small reddish lozenges, sometimes broken 
and single, sometimes united so as to form stars, rosets, or sheafs. 
These are all modifications of the simple rhomb or whetstone. 
(See Fig. 102 and Plate 7, Fig. 5.) 



THE URINE 599 

Practical Import. — Deposits of crystalline urates in the joints 
and kidneys are one expression of the gouty diathesis, in which 
there is a tendency for the nitrogenous waste to take this shape. 
Cases occur, not otherwise related to gout, in which the urine 
deposits free uric acid spontaneously. If this happen only in 
concentrated urine or when several hours have elapsed after 
micturition, and as a consequence of the acid fermentation, it 
may be ignored safely. The same crystals, however, seen in a 
sample soon after micturition should awaken the suspicion that 
the sediment likewise falls in the bladder or in the kidney. If 
persistent, these would aggregate into calculous masses. About 
80 per cent, of all the urinary concretions are composed of uric 
acid alone or mixed with urates. The solubility of these in 
alkaline fluids is the basis for preventive treatment by the liberal 
exhibition of the alkaline bicarbonates or citrates. 

Purin Bodies. — In another place (p. 489) consideration is 
given to the relationship held by uric acid to the other purin 
bodies, the xanthin bases, which are present in the urine in the 
proportion of 1 : 10 of uric acid. At the same place is discussed 
the distinction between endogenous and exogenous uric acid. 
We have complete control over the exogenous uric acid by regu- 
lating the diet so as to reduce the nucleins and purins to a minimum 
(p. 492). 

Mixed Urates. — Under this title are included salts of uric 
acid with sodium, potassium, and perhaps ammonium, magne- 
sium, and calcium, which in normal urine are soluble at ordinary 
temperatures. If, however, morning urine of ordinary acidity 
and density be kept in a cold room, its solvent powers are les- 
sened, and it may become turbid, forming a surface film and 
throwing down these mixed urates as a loose pink powder. Even 
at common temperatures this sediment may occur if the urine 
be very dense and of higher acidity than usual. In such cases the 
urates may not in themselves be in excess, but the urine, owing 
to hyperacidity, becomes a poorer solvent for them. These 
conditions are very frequent, and hence this deposit is a very 
familiar one; it is sometimes known as the lithate or the lateritious 
or the brick-dust deposit. It is not at all difficult to recognize, 
being the only deposit which clears up when the urine is heated. 
Again, it is dissolved when potassium hydroxid is added to the 
urine. The same procedures would leave a phosphatic deposit 
unchanged, or even increase the turbidity. In case of doubt 
the murexid test (see Uric Acid) would act with the urates. 
(Plate 7, Fig. 1.) 

Microscopically, the urates are found to be amorphous gran- 
ules with a tendency to form moss-like groups, pinkish in color 



6oo 



FOODS AND DIGESTION 




Fig. 102. — Uric acid and mixed urates (Funke). 



(Fig. 102). To distinguish them from amorphous phosphates, a 
drop of potassium hydroxid may be caused to flow under the 
cover. The urates will dissolve, but the phosphates are unaf- 
fected. (Plate 7, Fig. 4.) 

Practical Import. — By referring to the conditions producing 
them, it will be seen that before attaching much importance to 
this deposit it must be ascertained if the urine has been kept in 

a cold place. If not, then the 
deposit may be one evidence 
of excess of acid urates due 
to increased waste of nitrog- 
enous tissue, such as occurs 
in fever. This may be tran- 
sient, as from cold, or persist- 
ent, as in chronic diseases 
causing hectic iever. Some- 
times it is the expression of a 
habit of defective oxidation, 
or it may be assignable to a 
free indulgence in meats and 
heavy liquors. The urine can 
be cleared up quite easily by 
making it alkaline, and some- 
times by merely lowering its acidity. For this the usual remedy 
is potassium citrate in doses of J to 1 dr., given in an effervescent 
draught. If the urates be persistently deposited while the urine 
is in the bladder, they tend to accrete about a nucleus, and thus 
gradually form a concretion. 

Ammonium Urate. — This compound of uric acid has some 
properties differing from those of the mixed urates referred to 
above. It will form as a deposit in urine made ammoniacal by 
putrescence, and then appears in company with the triple phos- 
phate crystals. Under the microscope it is seen as dark-brownish 
spherules. Under this title some writers class a deposit made of 
irregular spherules with spiny projections. These have been 
called hedgehog crystals. Occasionally they look not unlike an 
acarus insect (Fig. 97). 

Practical Import. — The dark spherules are simply incidental 
to ammoniacal fermentation. The spiny globes are sometimes 
seen in the dense, scanty, high-colored urine passed by children 
in febrile attacks. Concretions are very apt to be formed by them 
if the attacks are of frequent occurrence. 

Sugar. — Sugar in anything more than a very minute amount 
is absent from healthy urine. Some of the urinary constituents, 
such as uric acid and creatinin, and the glycuronates of indol and 



THE URINE 60 1 

skatol, and a number of accidental drugs, can be made to exhibit 
reducing powers resembling those of glucose. In normal urine 
this power is not marked enough to appear distinctly with the 
usual reduction tests when properly made, whereas in true gly- 
cosuria it is shown to a pronounced degree. It is well to remem- 
ber that high-colored, acid, and dense urines contain a relatively 
large amount of uric acid and creatinin, and that with such sam- 
ples additional care should be observed to avoid a fallacy. It is 
always advisable before testing for glucose to make sure of the 
absence of albumin. 1 

Glucose as a Reducing Agent. — The most striking tests make 
use of the property possessed by glucose of reducing salts of 
copper and bismuth to lower oxids, or even to the metallic state, 
when boiled with these salts and an excess of alkali (Plate 8, 
Figs. 1-4). 

Trommer's test is made with \ in. of urine in the test-tube, to 
which is added an equal amount of potassium hydroxid (liquor 
potassae) and a few drops of a solution of copper sulphate. These 
.are heated over a spirit lamp or a Bunsens' burner until boiling 
begins. A red or yellow precipitate of cuprous oxid denotes glu- 
cose. This is a crude and sometimes fallacious method of testing 
with copper sulphate. To obviate its defects it is best to make 
the alkaline copper solution first and bring it to the boiling-point 
before adding the urine. But when the alkali and the copper sul- 
phate are mixed, an objectionable precipitate of cupric hydrate 
forms. The change into an insoluble hydrate can be prevented 
by adding certain carbon compounds, such as the tartrates, gly- 
cerin, mannite, and glucose. Of these, however, glucose only 
has the power to abstract oxygen from the boiling copper solu- 
tion, throwing down the red or yellow cuprous oxid (p. 302). 

The glycerin cupric test may be accurately applied by mixing 
in the tube an inch of potassium hydroxid, a few drops of copper 
sulphate solution, and a drop or two of glycerin. Having heated 
this mixture to boiling, about 10 drops of suspected urine should 
be added. After waiting a few seconds, if the yellow or red pre- 
cipitate does not appear, the mixture must be brought to the 
boiling-point again and a few drops more of urine added. This 
process must be repeated until the yellow or red precipitate 
appears or until the total contents of the tube reach 2 in. The 
yellow or red precipitate denotes glucose. In practice it is very 
convenient to have the glycerin and copper ready mixed. This 
is done by dissolving 28 gr. of copper sulphate in a mixture com- 

1 Artificial saccharin urine for students' practice can be made by adding to 
normal urine a small quantity of the ordinary syrup sold by grocers, which is 
mainly glucose. 



602 FOODS AND DIGESTION 

posed of J fl. oz. of water and J fl. oz. of pure glycerin. To make 
the test fluid, several drops of this are added to an inch of potas- 
sium hydroxid. Fehling's solution differs from the preceding in 
using a tartrate as the medium for making a clear alkaline copper 
fluid. It may be made and contained in a single bottle, but in 
that shape does not keep well, depositing the red oxid of copper 
spontaneously. It is better to have its components in two sep- 
arate bottles labeled A and B, of which equal parts are to be 
mixed when used. To make solution A, mix copper sulphate 
34.64 gm. and water enough to make 500 c.c. For solution B, 
mix Rochelle salt 173 gm., solution of sodium hydroxid (specific 
gravity 1.33) 100 c.c, and water enough to make 500 c.c. To 
make Fehling's solution mix equal parts of A and B. 

Fehling's test is made by putting about \ in. of the above solu- 
tion into a test-tube and diluting it with 2 in. of water. When 
heated to the boiling-point add a small amount of urine. If no 
red or yellow precipitate appears, heat to boiling again and add 
another instalment of the urine short of an inch in amount. Heat 
to boiling again and watch it as it cools; the slightest yellow or 
red turbidity would indicate glucose. 

In all the above copper tests care should be taken that the test 
fluid should exceed the urine in volume, and that the contents of 
the tube should not be boiled, but merely heated to the point of 
boiling and then withdrawn from the flame. 

Volumetric Estimation. — Having mixed in a porcelain capsule 
10 c.c. of Fehling's solution and 40 c.c. of water, the mixture 
should be heated over wire gauze until boiling begins. While 
thus heating a buret may be charged with a mixture of 1 volume 
of urine to 9 of water. This diluted urine should be allowed to 
drop slowly from the buret into the gently boiling test-fluid until 
the blue color of the copper solution totally disappears. Having 
noted the number of cubic centimeters required, if great accuracy 
be desired, the whole process may be repeated with fresh materials, 
dropping the urine very slowly as the reaction approaches its end. 
The solution has been standardized, so that 10 c.c. of it will be 
decolorized by 0.05 gm. of glucose. 1 If it be found that 7 c.c. of 
the dilute urine were needed, then, as the urine was diluted 1 part 
in 10, we read it 0.7 c.c. of urine = 0.05 gm. of glucose. Parts 
per hundred can be calculated by the ratio 0.7 : 0.05 :: 100 : x = 
7.14. To get grains to the fluidounce, the 7.14 must be multiplied 
by the factor 4.55. 

Purdy's Volumetric Method. — In practice the beginner finds 
that the Fehling's precipitate of copper suboxid obscures the 

1 The same quantity, 10 c.c, requires to reduce it, 0.067 g m - °f lactose and 
0.074 of maltose. 



THE URINE 603 

color indications and errors are frequent from this difficulty. To 
obviate it the solution for quantitative purposes is best made 
with ammonia, which holds the copper salts in solution. There 
is no precipitate to cloud the end-point of the reaction, and the 
change is sharp from the blue fluid to one that is yellowish. 

To make Purdy's solution, take copper sulphate 4.75 gm.; 
glycerin 38 c.c; dissolve in 200 c.c. of water by heat. In another 
200 c.c. of water dissolve potassium hydroxid, 23.5 gm., and mix 
with the copper glycerin solution. When cool, add strong am- 
monia water, 450 c.c, and water sufficient to make 1000 c.c. It 
makes a sapphire-blue solution. 

Method. — Put in a capsule or beaker 35 c.c. of the above 
solution and 70 c.c. of water. Put in the buret the plain urine. 
Boil steadily and add, drop by drop, the urine until the blue 
liquid is colorless and transparent. For the total cubic centi- 
meters of urine used calculate 0.02 gm. of sugar. If the quantity 
of urine used was 4, then 

4 c.c. = 0.02 
1 c.c. = 0.005 
therefore, the percentage or 100 c.c. = 0.50. 
If less than 4 c.c. are required, dilute the urine by adding 2 parts 
of water and then multiply the result by 3. The advantages 
found in students' work are the definite end-point, stability, 
rapidity, and accuracy. 

A fallacy results from the fact that the normal reducing power 
of urine from uric acid, creatin, etc., is equivalent to about 0.5 
per cent, of glucose. Hence some dense, high-colored urines 
may discharge the blue color after prolonged boiling, even when 
free from sugar. The whole titration must be done quickly, as 
the decolorized solution regains its blue color on standing a few 
minutes. 

Bbttger's Bismuth Test. — As albumin may interfere with this 
test owing to the sulphur it contains, it is desirable first to make 
sure that no albumin is present. If found, it can be separated by 
making the urine slightly acid with acetic or nitric acid, boiling, 
and when cool, filtering. About 1 in. of this urine (albumin-free) 
is put into a test-tube with 1 in. of potassium hydroxid and a pinch 
of bismuth subnitrate. The mixture, being boiled for several min- 
utes, will turn brown, and the white bismuth salt will turn gray 
or black if sugar be present. A convenient shape is given to the 
reagent by Nylander in the following solution, which contains 
both the alkali and the bismuth oxid: Take bismuth subnitrate 
2 parts, Rochelle salt 4 parts, and caustic soda (solution of 8 per 
cent.) 100 parts. Into a test-tube put 2 in. of urine and about \ 
in. of Nylander's solution. After boiling a few minutes change 



604 FOODS AND DIGESTION 

to a brown or black color would indicate glucose. The result 
with the bismuth test is not free from doubt until the fallacy due 
to sulphur compounds is eliminated. As they make a black 
precipitate with lead salts, which are not affected by glucose, 
litharge can be used to detect them. If, when litharge is substi- 
tuted for bismuth subnitrate in Bbttger's test, a brown or black 
color be produced, then sulphur compounds are present, and 
may cause a black precipitate, making the test for glucose. As- 
surance can be made doubly sure by trying Fehling's test, which 
is free from liability to this fallacy (Plate 8, Figs. 3,4). 

Picric-acid-and-potash Test. — About 1 in. of suspected urine 
is mixed in a test-tube with J in. of the saturated solution of picric 
acid and J in. of liquor potassium hydroxid. On boiling this 
yellow mixture for one minute a slight deepening of color may occur 
in normal urine, owing to reduction by uric acid and kreatinin; but 
change to a dark mahogany-red color would denote glucose. 

Phenylhydrazin Test. — Use an ordinary test-tube, and to J in. 
of dry powdered phenylhydrazin hydrochlorid add an equal volume 
of powdered sodium acetate and an inch and a half of urine. By 
gently heating to the boiling-point the sodium acetate dissolves; 
continue boiling for two minutes, and set aside for twenty minutes 
to permit the glucosazone to form. If sugar be present, the yellow 
deposit falls, and when examined under the microscope is seen to be 
chiefly sulphur-yellow needles of phenylglucosazone. Without 
sugar the deposit does not show needles, but scales and brownish 
globules. It gives a similar reaction with maltose, lactose, pentose, 
and glycuronic acid (Plate 3) (p. 481). 

Fermentation Test. — Reducing substances other than glucose, 
such as are derived from various drugs administered, are some- 
times present and render the observer liable to a fallacy if he depend 
on the reduction tests only. Glucose is the only substance yet 
found in the urine which in one hour will pass into the alcoholic 
fermentation (though lactose may ferment after a longer period), 
when brewers' yeast in compressed cakes is added to it and the 
mixture allowed to work in a warm place. After twenty-four hours 
the glucose will have disappeared, being resolved partly into carbon 
dioxid which escapes and partly into alcohol which remains. This 
breaking up of a dissolved solid into a lighter and a volatile part 
occasions a loss of specific gravity in the solution proportionate to 
the amount of the solid involved. Not only is this an excellent 
test for the presence of glucose, but by the Roberts method it is 
available for quantitative estimates. This differential-density pro- 
cess is simple, requiring an accurate urinometer, some brewers' 
yeast, and a bottle of urine. 

The specific gravity is carefully taken by a Mohr balance, a 



THE URINE 



605 



pyknometer, or a delicate urinometer, and recorded; then about 4 
oz. of the urine are thoroughly mixed with half a cake of com- 
pressed yeast and set aside in a warm place (the kitchen) for 
twenty-four hours. Fermentation will prove conclusively that 
the urine is saccharine. When the fermentation subsides, the 
specific gravity is taken again and compared with the first obser- 
vation. According to Roberts, each degree of density lost stands 
for 1 gr. of glucose to the fluidounce of urine. If percentage be 
desired, the product must be multiplied by 0.219. For example, 
if the specific gravity before fermentation was 1040 and that taken 
afterward was 1020, then 1040 — 1020=20 gr. of glucose to the 
fluidounce of urine. This 20 multiplied by 0.219 gives 4.38 per 
cent. Sometimes the test is performed by collecting the carbon 
dioxid gas. To do this a test-tube must 
be filled with a mixture of urine and 
brewers' yeast, the thumb put over the 
mouth so that the tube may be inverted, 
and the opening immersed in a deep 
saucer containing the same mixture. 
The inverted tube having been securely 
fixed must be kept for twenty-four hours 
in a warm place. If glucose be present 
to an amount exceeding 0.1 per cent., 
some gas will collect at the top of the 
tube. 

A more convenient and precise ap- 
paratus is Einhorri's fermentation sac- 
charometer. 

Method: Take one-sixteenth of a cake 
of compressed yeast, shake well in a 

test-tube with 10 c.c. of the urine; pour the mixture into the sac- 
charometer, and by inclining the apparatus the mixture easily 
flows into the tube, displacing the air. Set aside in a warm room 
for twenty-four hours. 

If the urine contain sugar, the alcoholic fermentation begins 
in about twenty to thirty minutes. The evolved gas gathers at 
the top of the tube, forcing the fluid back into the bulb. 

In twenty-four hours the upper part of the graduated tube is 
filled with carbon dioxid gas. The level of the fluid in the tube 
indicates by the numbers the approximate per cent, of sugar 
present. If the urine contain more than 1 per cent, of sugar, it 
must be diluted with water before being tested. Diabetic urines 
of a specific gravity of 1.018-1.022 may be diluted with an equal 
quantity of water and the result multiplied by 2; of 1. 022-1. 028, 
with 4 volumes of water, and the result multiplied by 5. 




Fig. 103. — Saccharometer and mixing 
tube. 



606 FOODS AND DIGESTION 

If we take, beside the urine to be tested, a normal one, and 
make the same fermentation test with it, the mixture of the normal 
urine with the yeast will have on the following day only a small 
bubble at the top of the tube. This proves the efficacy and purity 
of the yeast. If there be in the suspected urine only a small bubble 
at the top of the cylinder, then no sugar is present, but if there be 
a much larger volume of gas, then there can be no doubt that the 
urine contains sugar. 

Polariscope Test. — When the chemical tests give a doubtful 
report, the polariscope should be used (p. 61). 

Practical Import. — The presence of sugar in the urine, in 
amounts detected by ordinary tests or glycosuria, as it is called, 
proceeds from conditions regarded as essentially pathologic. In 
the majority of cases it is a sign of diabetes mellitus. In this disease 
the sugar is commonly abundant, averaging 4 per cent., but some- 
times reaching the large amount of 10 per cent, or 50 gr. in the 
fluidounce; it persists for many months and occasions the excretion 
of large quantities of urine, which may amount to 2 gallons daily, 
pale in color and of a mellow-apple odor. With the excess of water 
there is an increase in other natural constituents, such as urea. 
The total effect of these solids and the sugar is to raise the specific 
gravity above the normal point. At the same time there is an 
obvious breaking down of the health; the patient grows emaciated, 
notwithstanding his voracious eating and drinking. The amount 
of sugar excreted and the cognate symptoms are measurably under 
the control of a dietetic regimen. By cutting off saccharine and 
amylaceous foods from the dietary, not only the proportion of 
sugar in the urine, but also the fluid volume, can be lessened. 

It remains to be said that glycosuria is sometimes transient 
and slight. In some individuals, usually obese, it may appear as. 
a consequence of excess in saccharine or amylaceous food. Tem- 
porarily, glucose, glycuronic acid, alkapton, pentose, or some other 
substances giving the same reduction reactions, though not fer- 
mentable, have been found after the administration of ether, chlo- 
roform, chloral, morphin, amyl nitrite, turpentine, salicylic acid,, 
salol, benzoic acid, glycerin, camphor, carbolic acid, strychnin,, 
arsenic, phosphorus, sulphonal, acetone, mercuric chlorid, phlor- 
izin, adrenalin, urotropin, and carbon monoxid. Glycosuria may 
complicate various diseases of the brain and spinal cord, cir- 
rhosis of the liver, cholera, phthisis, pneumonia, and asthma. It 
may appear in the last month of pregnancy and disappear soon 
after parturition. 

Pentosuria. — Traces of pentoses (C 5 H 10 O 5 ) (p. 437) are some- 
times found in the urine after ingestion of fruits, wine, and beer, 
and also as a result of family predisposition. The pentoses reduce 



THE URIXE 607 

Fehling's solution, but not in the amounts usually found. They 
yield good crystals with phenylhydrazin, but they do not respond 
to the fermentation test and are optically inactive. Their presence 
is detected bv Tolleris orcin test. The reagent is made bv mixing 
orcein, 1 gm.; liq. ferri chloridi, 25 drops, and 500 c.c. of 30 per cent, 
hydrochloric acid. Of this solution 5 c.c. are boiled in a test-tube 
and after removal from the flame a few drops of urine are added. 
If a fine green color does not form, more urine is added — up to 
1 c.c. This reaction is not given by normal or diabetic urine. 

Practical Import. — No bad results have been noted in the few 
cases studied. From the mistake in diagnosing pentosuria for 
diabetes the patient may lose the privilege of life insurance or be 
subjected to a diabetic regimen which has no effect on the pentose. 
Pentosuria is usually discovered by the failure of dietetic regimen 
to influence the reducing substance in the urine. 

Glycuronic Acid.— Glucose being CH 2 OH (CHOH) 4 COH, 
when oxidized in the body, the alcohol group CH 2 OH gives up H 2 
and takes O instead, thus changing to glycuronic acid, CO OH .- 
(CHOH) 4 COH. As this retains the COH group, it reduces 
Fehling's solution. It is found in the animal body and a bare 
trace in human urine, combined with indoxyl and phenol. Larger 
quantities appear in the urine after the administration of chloral, 
camphor, naphthol, turpentine, menthol, toluol, exalgin, morphin, 
etc. It forms compounds which are closely allied to the glucosids. 
The compounds vary according to the drug with which it is united — 
campho-glycuronic acid, menthol-glycuronic acid, etc. The free 
acid and the above glycuronates reduce the oxids of copper and 
bismuth in alkaline solution; hence, they may be confounded with 
glucose. But, unlike glucose, it does not ferment with yeast. .Its 
presence is suspected when a sample of urine reduces Fehling's, 
Bbttger's, or Nylander's solution, but it is levorotatory to polarized 
light, and does not ferment with yeast (p. 436). 

Acetone (CH 3 . CO . CH 3 ), Diacetic Acid (CH 3 . CO . CH 2 - 
COOH), and Beta=oxybutyric Acid (CH 3 . CHOH . CH 2 . - 
CO OH). — These substances are closely related, as shown by the 
formulas, and by the fact that diacetic acid is changed to acetone 
by heat. A trace of acetone is usually found in diabetic urine 
and sometimes in healthy urine. When diabetic coma is impend- 
ing, there is a large increase of acetone in the urine and diacetic 
acid appears, while the specific gravity, the sugar, and the urea 
decline. The diacetic acid is revealed by adding 1 or 2 drops of 
liquor ferri chloridi to 3 c.c. of urine. A yellowish phosphatic 
precipitate forms, which should be separated by filtration. If 
the filtrate, when treated with a few more drops of the ferric chlorid, 
does not yield a claret-wine color, we may safely infer the absence 



608 FOODS AND DIGESTION 

of the significant substance. If the wine color appear when the 
patient is not taking salicylic acid, antipyrin, kairin, or other phenol 
products, it is most likely due to diacetic acid. More elaborate 
control-tests can be applied to make the result conclusive, such as 
boiling a fresh sample, which destroys the diacetic acid and prevents 
the ferric chlorid reaction unless that be due to the indifferent 
phenol products referred to. Should the boiled sample yield no 
reaction, another portion acidulated with dilute sulphuric acid and 
extracted with ether may give the dark-red color when the extract 
is treated with ferric chlorid. This denotes that the diacetic acid 
existed in combination. 1 (Plate 8, Fig. 6.) 

For minute quantities it is necessary to concentrate the acetone 
by distilling 10 c.c. from ioo c.c. and applying the tests to the 
distillate, or a more delicate method may be preferred. Take 50 c.c. 
of urine, add a few drops of sulphuric acid, and shake well with 
50 c.c. of ether. The ether extracts the acid from the other 
urinary constituents and forms a top layer. Separate the ether 
and shake the extract with a small quantity of weak solution of 
ferric chlorid. Diacetic acid turns it red; salicylic acid turns it 
red violet (pp. 426 and 468). 

Legal's Test for Acetone. — Mix 25 c.c. of urine with 25 c.c. of 
a strong, freshly made solution of sodium nitroprussid, and add a 
few drops of sodium hydroxid or strong ammonium hydroxid. 
Acetone develops a red color, and, on the addition of acetic acid, 
in one or three minutes becomes darker. Creatinin gives the red 
color, but it disappears on adding acetic acid. 

There is no simple reaction for beta-oxybutyric acid. If the 
glucose be removed by fermentation with yeast, and then the clear 
urine tested with the polariscope, a decided rotation to the left 
points to this acid. Its specific rotation is 24. Then a rotation of 

i° with a 2 decimeter tube would give —=2 per cent. Slight 

degrees of levorotation would mean nothing, as normal urine is 
slightly levorotatory. 

Practical Import. — The presence of acetone, like that of dia- 
cetic acid, and beta-oxybutyric acid with glucose in the urine, renders 
the diagnosis of diabetes certain. The gravity of the disease is pro- 
portionate to the "acetone bodies" in the urine. The maximum 
quantity may be more than 5 gm. in twenty-four hours. Death 
from diabetes is often preceded by a typic coma beginning with 
indigestion, abdominal pain, weakness, and drowsiness. These 
symptoms have been attributed to an acid intoxication by the beta- 
oxybutyric and diacetic acids, which alter to a dangerous extent 

1 For the students' practice, ethyl aceto-acetate, a few drops, may be added to the 
urine. It yields the same reaction as diacetic acid. 



PLATE 8. 

THE MOST IMPORTANT COLOR-REACTIONS OF THE 
URINE. 

Figs. 1 to 3. Trommer's Test for Sugar. — Potassium hy- 
droxid and copper sulphate. 

Fig. 1. Urine free from sugar does not dissolve copper sulphate 
and assumes a greenish -yellow color on boiling. 

Fig. 2. Urine containing sugar dissolves the hydrated cupric. 
oxid formed, with the development of a blue color, and precipi- 
tates on heating hydrated cuprous oxid in yellowish-red clouds 
(Fig. 3) — reduction-process. 

Fig. 4. Bismuth -test. — Addition of Nylander's solution. 
On heating, metallic bismuth is precipitated in black clouds if 
sugar be present. 

Fig. 5. Moore's (Caramel-) Test. — If to urine containing 
sugar is added one-third the quantity of potassium hydroxid and 
heat applied (for three minutes), a chestnut-brown color results. 

Fig. 6. Ferric-chlorid Reaction in Diabetes. — This con- 
sists in the development of a Bordeaux-red color when diacetic 
acid is present in the urine, and is thought to indicate threaten- 
ing diabetic coma [?]. 

Fig. 7. Peptone-test. — When albumoses, etc., are present in 
the urine the addition of potassium hydroxid and solution of 
copper sulphate in the cold is followed by the development of a 
violet color. 

Fig. 8. Indican-test. — If urine and pure hydrochloric acid 
be mixed in equal parts, and calcium hypochlorit in solution 
be added drop by drop, any indoxyl present will be oxidized into 
blue indigo (various intestinal disorders, fermentative processes). 
The mixture may be further shaken with chloroform or ether. 

Fig. 9. Test for Biliary Coloring-matter. — On shaking 
with chloroform the urine from a case of jaundice the fluid 
assumes a yellow color (bilirubin). 

Fig. 10. Heller's Blood-test. — On the addition of one-third 
potassium hydroxid and boiling, the precipitated phosphates 
carry the blood coloring-matter with them to the bottom in the 
form of red clouds. 

Fig. 11. Test for Melanin. — In cases of melanotic sarcoma 
the urine treated with iron chlorid* assumes a deep-black color. 

Fig. 12. Diazo-reaction. — In cases of typhoid fever, tuber- 
culosis, etc., the addition of a mixture of sulphanilic acid and 
sodium nitrite gives rise to the development of a bright-red 
color, apparent also in the froth on shaking. 

(Jakob.) 



PLATE 8c 











m 


1 


B 

HE 

m 










/////. Anst. I' Rnchlwhl. Munch en 



THE URINE 609 

the normal alkaline salts of the blood. This condition has received 
the name acidosis. The coma attending it results from the fact 
that the inorganic alkalis, such as sodium bicarbonate, NaHCO s , 
being neutralized by the acids, can no longer carry C0 2 away from 
the tissues where it accumulates, producing the phenomena of 
asphyxia (p. 423). 

Albumin. — Of the several protein compounds found at times 
in the urine, the two of greatest pathologic import are serum- 
albumin and globulin. These two have certain differences, but 
they are both derived from the blood under like conditions and 
appear together in the urine. In practice it is not necessary to 
discriminate between them. Other protein bodies, such as mucin, 
nucleo-albumin, peptone, and albumose, have, however, each a 
significance entirely different from that of albumin, though some 
of their reactions are similar. When albumin escapes into the 
urine it remains dissolved, as it does in the blood-serum, and can 
only be detected with certainty by tests which change it to an in- 
soluble compound called a coagulum. 1 This coagulum is per- 
manent, and not a precipitate to clear up by the action of reagents. 

Boiling Test. — Should the sample be cloudy, the portion to be 
tested must first be freed of suspended matter by filtration. This 
is easily and quickly done by resting the cone of filter-paper in 
the mouth of a test-tube. In a few minutes enough will be col- 
lected. When .the turbidity is due to urates and apparatus for 
filtration is not at hand, gentle heat will serye to clear up the 
urine, and then, by continuing the heat to the boiling-point, the 
cloud of coagulated albumin will appear. The congeners serum- 
albumin and globulin are the only proteins that coagulate in acid 
fluids at 70 C. (160 F.), or even at ioo° C. (212 F.), the boiling- 
point, to which the heat is usually carried. The test is best made 
with about 3 in. of urine in the tube, and if the reaction be not 
acid, it must be made so with one drop of acetic acid. Holding 
the tube aslant, the flame of the alcohol lamp or Bunsen's burner 
should be applied to the upper half only, while the tube is slowly 
revolved. It is advisable to continue heating until boiling begins. 
If albumin be present, the heated half grows more or less cloudy, 
as contrasted with the unchanged lower half. Three points must 
be emphasized: first, if the urine have its normal acid reaction, it 
is not necessary to add acetic acid; second, even when it is neutral 
or alkaline, only one drop of the acid should be used, lest the albu- 

1 Artificial albuminous urine for students' practice may be easily made by put- 
ting the white of one egg in a bottle containing 3 fl. oz (or 100 c.c.) of a 2 per cent, 
aqueous solution of sodium chlorid, then shaking well and filtering. The filtered 
liquid can be kept indefinitely by adding 1 fl. dr. (or 4 c.c.) of chloroform. To 
make a sample closely resembling pathologic urine, add 10 c.c. of this liquid to 
100 c.c. of normal urine. 

39 



6lO FOODS AND DIGESTION 

min should be converted into acid-albumin, which is not coagu- 
lated by heat; and, third, phosphates are sometimes precipitated 
by boiling off the dissolved C0 2 from a slightly acid specimen, but 
this precipitate clears up on cooling or on the addition of acid. 
If the white clouds appear in the boiling half, the test must be com- 
pleted by adding a jew drops of nitric acid while the urine is hot, 
but without further boiling; the albumin coagulum persists while 
the precipitated phosphates dissolve. When there is suppression 
of urine, the amount obtainable may be but a few drops, which is 
not enough for a satisfactory result by boiling the urine. A dis- 
tinctive result can be had by boiling some water in a test-tube, 
acidulating, if necessary, and letting a drop or two of urine fall 
into and mix with the hot water. A white cloud forms if albumin 
be present. 

This test is available for making an estimate of the proportion 
of albumin. If the entire contents of the tube be boiled for a few 
minutes, and then set aside for twenty-four hours, the flakes of 
albumin will fall, so as to make a layer the volume of which can be 
stated as compared with the total depth of urine in the tube; thus, 
"the sample had to or "i" moist albuminous layer.' ' It will be seen 
that this does not mean that the urine contains tV or \ part by 
weight of albumin. 

Nitric-acid Test. — Heller's Method. — If the urine be turbid, it 
must be made clear by pouring it through a cone of filter-paper 
set in the mouth of a test-tube. Having about 2 in. of clear 
urine, the tube should be inclined and nitric acid allowed to 
trickle down the glass, so as to form a bottom layer of about J in. 
in depth. If the acid be introduced at the bottom by means of a 
pipet, a more distinct line of separation will be secured. After 
five or ten minutes, if appearances be doubtful, the tube should be 
held so that the light falls on it in such a way as to show up any 
haziness that may have formed. A more or less wide and distinct 
white belt at the line of contact of acid and urine indicates albumin. 
While this test used cold is not quite so sensitive as that by boiling, 
there are very few cases of serious albuminuria that cannot be 
detected by it. By keeping the acid and the urine separate, except 
at the line of contact, we ensure that at some point there will be 
just the amount of acid needed to coagulate the albumin. A red- 
dish zone is often formed by the oxidation of normal urorosein. 
This method keeps the upper part of the urine unchanged, so as to 
be a standard for comparison. There are cases where the reaction 
is so questionable as to make this standard of decided value. 
Occasionally a dense urine so treated will throw out a cloud of 
urates J in. nearer the surface, but not at the line of contact. 
Sometimes a faint band of precipitated proteins other than 



THE URINE 



611 



albumin appears about one centimeter above the line of contact. 
All the precipitates except albumin clear up when heat is applied. 
In all cases it is best to use both heat and nitric acid. 

A quick and handy method, useful when the amount of urine 
is small or when there are many examinations to be made, as in 
hospitals or dispensaries, is to dip a pipet of \ in. caliber into the 
urine, taking up about i in., and then dipping the same into nitric 
acid 2 in. deep, relaxing the ringer pressure so as to admit the 
acid. The finger is pressed down firmly again, the pipet lifted from 
the acid, and held so that a good light falls on the contents. If no 
change occurs, we may infer that albumin is absent. If albumin 
be present, within one minute a sharp white ring is formed at 
the contact line. Albumose and urates form a white cloud with 
cold nitric acid when weakened by dilution, but higher up the 
tube than the line of contact with nitric acid. To make the 
albumin ring more positive it is desirable to apply the boiling test 
in addition to another acidulated portion in a test-tube. 

Picric-acid Test. — The reagent is a saturated solution made by 
dissolving 6 gr. of recrystallized picric acid in i fl. oz. of hot water, 
and after standing for a time decanting the clear fluid. The urine 
must first be free from turbidity: if necessary for 
this, it may be dropped through a cone of filter- 
paper into the test-tube until about 3 in. col- 
lect. The picric acid is then permitted to flow 
down the side of the tube held slanting to prevent 
the two fluids mixing. The yellow reagent re- 
mains on top, and if albumin be present, a more 
or less cloudy zone will immediately form in the 
urine as far as the picric acid diffuses downward. 
If the upper part of the turbid zone be heated to 
the boiling-point, haziness due to albumin will 
increase, and if the tube be set aside will sub- 
side as a compact stratum resting on the un- 
changed column of urine below. 

Beside albumin, the acid urates' and several 
occasional constituents, such as mucin, albumose, 
peptone, semen, and the alkaloids, will yield an 
opalescence to picric acid. But the albumin and 
semen cloud is peculiar in that it persists after 
heating. This is a very delicate test; indeed, it 
sometimes reveals albumin in amounts so small 
as not to have significance for the practitioner. Fig. 104.— Esbach's 

—,, . . j . ,- .. .1 albuminometer. 

1 he same reaction is employed in estimating the 
weight of albumin by Esbach's albuminometer. This is a test- 
tube of strong glass graduated in the manner shown in Fig. 104. 




6l2 FOODS AND DIGESTION 

The test solution is prepared by dissolving 10 parts of picric 
and 20 of citric acid in 900 of boiling distilled water. After 
cooling, a sufficient quantity of water is added to make a total 
of 1000 parts. The object of the citric acid is to ensure that the 
liquid shall overcome any possible alkalinity in the urine. The 
graduated tube is filled with clear urine up to the mark U, and then 
the reagent up to R. It is then closed with a stopper, and the 
two liquids are thoroughly mixed in such a manner as to avoid 
shaking by slowly reversing the tube about ten times. Quick 
agitation might make air-bubbles that cause the precipitate to 
float. These must be removed with a pipet. After standing up- 
right for twenty-four hours, a dense and well-defined coagulum 
of albumin falls. The height of this sediment, read off on the 
etched scale, will indicate the weight of dried albumin in parts per 
thousand of urine (grams per liter). While this process yields 
results which within a certain range are fairly accurate (an error 
of one-tenth to two-tenths of albumin), it is far more convenient 
than the tedious and difficult, though more accurate, method of 
separating the albumin by heat and acid and, after filtration, weigh- 
ing the dried precipitate. Esbach's process will not give correct 
statements of amounts less than 0.5 parts per 1000. When the 
proportion of albumin is very high — that is, when the coagulum 
stands above 4 on the scale — it is best to dilute the urine with 1 or 2 
volumes of water, and after testing multiply the result by 2 or 3, 
according to the degree of dilution. 

In addition to the time-honored tests already given, which have 
the confidence of the profession and the sanction of much usage, 
there remain to be described several others of great sensitiveness, 
but not sufficiently discriminating. 

Tanret's potassiomercuric iodid reagent is composed of mer- 
cury bichlorid 1.35 gr., potassium iodid 3.32 gr., acetic acid 20 c.c, 
distilled water enough to make 1000 c.c. By the contact method 
it shows a white belt with albumin, but also with other proteins 
whose presence may not be at all significant. The same objec- 
tion can be made to the solutions of sodium tungstate, of meta- 
phosphoric acid, and the more complex acetic-] err ocyanid test. 
The last named is of extraordinary delicacy. It is applied by 
first making the urine decidedly acid with acetic acid, and then 
adding a few drops of recently prepared solution of potassium 
ferrocyanid. It precipitates albumin, but also albumose and 
peptone. 

Purdy's Quantitative Method for Albumin (Centrifugal). — 
The centrifuge estimation by volume is performed by putting into 
the percentage tube 10 c.c. of urine. To this is added 2 c.c. of 50 
per cent, dilution of acetic acid and 3 c.c. of a freshly made 10 per 



THE URINE 



6l 



cent, solution of potassium ferrocyanid. After shaking the mixture 
and standing aside ten minutes it is rotated for three minutes at 
1500 revolutions per minute. For every ys c - c - of precipitate 
calculate 1 per cent, by volume of albumin layer. From this it 
is easy to find the percentage of dried albumin or grains per fluid- 
ounce by consulting the following table: 



Purdy's Table jor Estimating Albumin 

This table shows the relation between the volumetric and gravimetric percentage 
of albumin obtained by means of the centrifuge with radius of 6f in. ; rate of speed, 
1500 revolutions per minute: time, ; minutes. 





-. 


^ . 




- 
- 


1 


3 





- 


- 
u 


bfl 




g 


: u 


*1 




- - 


*5 


- . 

4 5 


: i 


1 s 


= 

i = 


■- jjj 


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6 14 FOODS AND DIGESTION 

A recently introduced test is that by trichloracetic acid. It is 
best used as a solution (specific gravity, 1.147) after the contact 
method. A white clot forms next to the reagent when albumin 
or albumose is present; boiling will dissipate any cloud not albu- 
minous. 

For salicylsulphonic acid as a test see Albumose (p. 615). 

Practical Import. — Except in certain rare cases, such as the 
cyclic albuminuria of adolescents, albumin is an indication of a 
serious disturbance in the function of the kidney. It is generally 
conceded that in the early hours of the day a trace af albumin 
can sometimes be found in the urine of young men otherwise in 
apparent health. It is probable that even in these persons there 
is an alteration in the kidney, though it may be one removable by 
time or medication. In small amounts it is often seen at certain 
stages of severe specific fevers and blood-poisonings, and just 
after epileptic seizures. In 60 per cent, of pregnant women a 
trace of albumin appears some time after the fifth month. This 
is incidental to the pressure of the gravid womb on the renal cir- 
culation. With few exceptions, the urine becomes normal soon 
after delivery of the child. Poisoning by lead, arsenic, and some 
other metals may occasion it. In every such case the question arises: 
Can the albuminuria be regarded as a sign of Bright's disease of the 
kidneys? The answer will be affirmative if the symptom prove 
persistent and the layer produced by the boiling test should equal 
one-half of the column of urine in the tube. For proof positive 
we must examine the sediment with the microscope for tube-casts. 

The general condition must be considered, and would be re- 
garded as highly confirmatory if characterized by anemia, cardiac 
hypertrophy, or dropsy. With these even a mere trace of albu- 
min must be held to be of very grave import. Reactions of albu- 
min with blood may be due simply to the hemorrhage, which may 
come from any part of the genito-urinary tract. W T hen found 
with abundance of leukocytes, it may be due to the fluid of pus, 
and have no other significance. 

Mucin (Nucleo-albumin). — This is a constituent of mucus 
which is coagulated by the organic acids — acetic, citric, picric, and 
trichloracetic. With Heller's test it forms a cloud, not next to the 
nitric acid, but high up the tube. To discriminate, the urine must 
be boiled, when all clouds disappear except the one made by serum 
albumin. 

Albumosuria. 1 — Proteoses or albumoses belong to the family 
of proteins, sometimes found in the urine. They appear in small 
amounts in various infectious diseases, and are often referable to 

1 Artificial albumose urine for students' use can be made by dissolving in the 
urine some Witte's dry peptone. 



THE URINE 615 

resorption of disintegrated pus. While soluble in dilute salt 
solution, they are precipitated when the solution is saturated with 
ammonium sulphate. Heat does not coagulate them. 

Tests. — To get significant amounts it is often necessary to 
evaporate the urine on a water-bath to less than half its volume. 
Into a large test-tube put 2 or 3 in. of urine with an equal volume 
of saturated solution of common salt, and about J in. of acetic acid. 
A precipitate forms if albumose be present, the urine clearing up 
on boiling and the precipitate reappearing on cooling. If it does 
not clear up on boiling, then other proteins are present and must be 
filtered off while hot. The return of the cloud as the hot filtrate 
cools signifies albumose. 

If the hot filtrate be carefully poured down an inclined test- 
tube so as to form a layer with 1 in. of Fehling's solution, a rose- 
pink halo {biuret reaction) will appear at the line of contact (PI. 8). 

Salicylsulphonic-acid Test. — A convenient and sensitive reagent 
for distinguishing albumin and nucleoproteins from albumose 
is made by treating salicylic acid with sulphuric acid and crys- 
tallizing by evaporation. The crystals of salicylsulphonic acid 
may be safely carried about in the pocket, or, better still, a bottle 
of saturated solution in water may be used. 

Method. — Two test-tubes are half filled with urine, and to each 
is added 1 c.c. of the solution. Shake both tubes well. If a 
cloudiness appear, we know that some form of albumin or albumose 
is present. Reserving one tube as a standard, the other is heated 
and then compared with the standard to see if heat have cleared up 
the cloud. If due to primary albumoses, it clears under heat, to 
reappear on cooling. If due to serum-albumin or nucleo-albumin, 
the cloud persists, unchanged by temperature. 

This test acts in acid and alkaline urines equally well, and does 
not precipitate phosphates, urates, uric acid, bile, alkaloids, or 
drugs. In delicacy as a test for albumin it stands between Heller's 
cold nitric-acid and the boiling tests. Its delicacy may be counted 
as an objection, for quantities of albumin too small to be of patho- 
logic importance may be shown. The most serious objection is 
the readiness with which nucleoproteins are precipitated, as at 
present we have no means of readily distinguishing this precipitate 
from that caused by albumin. The best check on these two falla- 
cies is obtained by the use of Heller's cold nitric-acid test in doubt- 
ful cases. The secondary ring higher up than the line of contact 
of acid and urine, given with nucleoproteins by this test, is readily 
recognizable. By diluting the urine one-half, the doubt as to the 
significance of the amount of albumin is set at rest. If the albumin 
reaction is obtained with the dilute urine, the amount is of patho- 
logic importance. 



6l6 FOODS AND DIGESTION 

Practical Import. — When active suppuration is going on any- 
where in the body and inflammatory effusions are breaking down, 
albumose is a product of autolysis of the pathologic tissue. It 
enters the systemic circulation, and is eliminated by the kidney. 
It may thus help to prove the existence of concealed internal suppur- 
ation. According to the cause, it has been divided into four 
classes — pyogenic, inorganic, enterogenic, and puerperal. 

The Bence=Jones protein is a rare urinary constituent closely 
related to the water-soluble globulin of the blood, and is recognized 
by the following tests: At a temperature of 60 ° C. (140 F.) it 
forms a gelatinous coagulum; at 8o° C. (176 F.) it clears, and at 
100 ° C. (212 ° F.) it is nearly all dissolved. 

Nitric acid makes a dense precipitate which disappears when 
warmed and returns on cooling. 

Acetic acid, up to 30 per cent., has no effect, but at 50 per cent. 
a jelly forms in five minutes which liquefies on warming. Salicyl- 
sulphonic acid causes a copious precipitate which dissolves when 
-heated, to reappear on cooling. 

Practical Import. — This protein appears in the urine in 
advance of myeloma and kindred diseases of the bone and 
marrow. It is always of grave significance. 

Hematuria. — Blood imparts to urine the reaction of albumin 
contained in serum and a red or brown color due to the corpuscles. 
The change of color and the albumin reactions may be found in 
hemoglobinuria, a condition in which the distinct corpuscles are 
not found, the color principle being diffused. 1 

The characteristic feature of true hematuria is the red blood- 
corpuscle. These biconcave bodies will preserve their peculiar 
form for several days if the urine containing them is of ordinary 
density and acidity. In a very dense urine they lose their smooth 
outline and become crenated. In a dilute medium they swell 
up to a spheric shape and grow pale. In the ammoniacal urine 
which usually attends cystitis they are apt to shrivel and be de- 
formed. 

Practical Import. — Hematuria is a symptom of .hemorrhage 
from some part of the genito-urinary tract. When the bleeding 
is at the kidney, the blood is usually well mixed with the urine, 
giving it a smoky-red appearance, and when the sediment falls, 
bloody renal tube-casts can be found with the microscope. It 
denotes active local mischief, or may be symptomatic of severe 
fevers or neurotic or toxic or vicarious to menstruation and hem- 
orrhoids. Blood from the ureter is apt, before evacuation, to form 

1 Artificial bloody urine can be conveniently prepared from fresh blood or from 
blood preserved in glycerin or from scales of dried blood kept on hand. When 
needed, the scales are ground up in a mortar with water and filtered. The filtrate 
may be added to normal urine. 



THE URINE 617 

clots which are molded in that tube in the shape of curved cylinders, 
looking to the naked eye like small worms. They have been mis- 
taken for parasitic entozoa. The microscope shows them to be 
a compact mass of red corpuscles. They may be due to local 
disease or injury, or incidental to the passing of a renal calculus. 
Blood from the bladder is usually abundant and gives to the urine 
a bright red color, with shreddy clots visible to the naked eye. It 
is accompanied by vesical symptoms, such as pain in the supra- 
pubic region and perineum, with frequent micturition and stran- 
gury. Blood from the urethra occurs in the course of gonorrhea, 
and reveals its source by local symptoms and by escaping at the 
meatus in the intervals of micturition (Plate 7, Fig. 3). 

Heller's test for blood-pigment is made by adding one third potas- 
sium hydroxid and boiling until flocculi of phosphates form. As 
they fall they carry with them the blood-pigment and become brown 
or red-yellow. Having collected the precipitate on a filter, it dis- 
solves in acetic acid with a red color, which gradually fades on ex- 
posure. It is an easy and satisfactory test (Plate 8, Fig. 10). 

Benzidin Test. — A much more sensitive test for blood-pigment 
is made by treating 10 c.c. of urine with 1 c.c. of glacial acetic acid. 
To this mixture a third volume of ether is added, well shaken and 
set aside. The supernatant layer of ether separates more quickly 
if 5 to 10 drops of alcohol be shaken with the mixture. With a 
pipet the ether is transferred to another test-tube containing the 
benzidin reagent, which has previously been made by mixing 0.5 c.c. 
of a freshly prepared solution of a little benzidin in 2 c.c. of glacial 
acetic acid with 2 or 3 c.c. of hydrogen dioxid. 

If blood is present, the reagent turns green or blue in two minutes; 
after five minutes it changes to a dirty purple. The test is both 
accurate and reliable to the extent of a negative result, excluding 
the possibility of blood. As there are a number of substances 
which give the same reaction, if a positive response be obtained, 
this must be confirmed by the guaiac and the hemin tests (p. 529). 

Hemoglobinuria. — In certain dissolved states oj the blood the 
coloring-matter is set free from the disintegrated corpuscles and 
eliminated by the kidneys. It imparts to the urine a dark-brown 
color. The albumin reaction is obtained by all the tests for that 
substance. However, the coagulum formed is not white, but red 
or brownish. To distinguish this condition from hematuria the 
microscope is necessary. 

In hematuria we not only have the color and the albumin re- 
action, but also the red corpuscles. The latter are not found in 
hemoglobinuria. With the spectroscope the dark bands of reduced 
blood-pigment can be identified by the special means employed 
with that instrument (Plate 4, Fig. 1, f-h). Almen's test by 



6l8 FOODS AND DIGESTION 

overlaying with urine a mixture of tincture of guaiac and a solution 
of hydrogen peroxid (or old ozonized oil of turpentine) gives a 
characteristic blue color (pp. 538 and 563). 

Practical Import. — Hemoglobinuria occurs in various blood 
diseases, microbic and otherwise, such as typhus, purpura, and 
pyemia. Sometimes it is the result of the toxic action of hydrogen 
arsenid, phosphorus, carbolic acid, chloral, or potassium chlorate. 
Certain individuals suffer from a periodic form, often attributable 
to cold or malaria, and sometimes of doubtful origin. 

Bile. — In conditions causing jaundice we can always find bile- 
pigment in the urine, but the biliary acids are seldom present in 
amounts great enough to give the lake-colored reaction w T ith the 
well-known Pettenkofer's test by cane-sugar and sulphuric acid 
(Plate 8, Fig. 9). 

Oliver's test for biliary acids, peptone solution, is very sen- 
sitive, but gives results so uncertain as not to merit detailed 
description in a practical study of the urine as brief as this is 
required to be. On the other hand, the bile-pigment can be 
detected in the urine of icterus even earlier than it will show 
itself on the conjunctiva. When notably present, it gives tints 
varying from bright sulphur yellow to olive green. 

Gmelin's test for biliary pigment is very sensitive and easily 
performed. A few drops of the suspected urine are poured in a 
white plate, and near them a small amount of yellow nitric acid 
(containing lower oxids of nitrogen). Having caused the two 
fluids to touch edges, bile-pigments will change at the line of contact 
into modified pigments. There will be a play of colors in regular 
order — green, blue, violet, red, and yellow. Green and red domi- 
nate, and will persist after the others fade. The same test can be 
applied in a tube by overlaying the nitric acid with the biliary 
urine. 

Practical Import. — A trace of bile found will help to diagnose 
hepatic troubles when the icterode hue elsewhere is doubtful. 

Pyuria. — It has been stated above that sometimes the albu- 
minuria may be due to pus, the fluid of which is albuminous. The 
distinctive elements of pus are the numerous leukocytes. These, 
under the microscope, can be recognized by their resemblance to 
the white blood-cells. They are spheric, granular, and opaque, 
but on the addition of acetic acid lose their opacity and show at 
the center one, two, or three nuclei. One cannot be sure from 
the form whether the leukocyte is derived from mucus or from pus. 
With the former comparatively few are to be found, with the latter 
a great number. Mucus can be further distinguished from the 
pus from the fact that the proteid mucin will not become hazy with 
heat and nitric acid, while the albumin of liquor puris coagulates 



THE URINE 619 

like serum-albumin. Again, if the suspected sediment be separated 
by decanting the upper part of the urine, and then into the deposit 
a piece of caustic potash is stirred, if the deposit be pus, it becomes 
tough and gelatinous; if mucus, thin and flaky (Plate 7, Fig. 2). 

Practical Import. — If pyuria, the albumin reaction raises the 
question as to whether in addition to pus there is serum-albumin 
of renal origin. We are helped to a conclusion by the fact that 
the albumin in pyuria is usually scanty, and a large amount would 
therefore be considered as over and above that due to pus. If tube- 
casts are found with the microscope, then renal mischief can be 
assumed. A sudden irruption of pus would most likely be due to 
the evacuation of an abscess into the genito-urinary passages. 
Persistent pyuria points to chronic catarrhal inflammation, the site 
of which can be determined by local symptoms. 

Chyluria. — Chyle is rarely found in the urine. At first sight 
of a sample containing it one would suppose that milk had been 
added to it. It may happen that the amount of chyle present is 
so large that the fat particles rise like the cream on milk, and the 
fibrin of the chyle may form a spontaneous clot, resembling blanc- 
mange. As the chyle contains serum-albumin, it would respond 
to the tests for that substance. To make out the fatty character 
of the molecular basis, a portion of the urine should be agitated 
with ether and potassium hydroxid, which dissolves the envelops 
and melts the fat particles together as a surface layer, leaving the 
urine clear beneath. The microscopic character is much like 
that of milk — that is, it contains myriads of small, bright, round 
particles which dissolve in ether. To eliminate the chance of 
deception from milk, the patient can be required to urinate in the 
presence of a witness. 

Practical Import. — This symptom generally appears in those 
who have lived in the tropics, where it is not very uncommon. 
It denotes a lymphatic connection with the urinary passages, and 
not infrequently is associated pathologically with the presence of 
Filaria sanguinis hominis. 

Epithelium. — Ordinarily the urine is clear, but even in health 
it occasionally shows a faint cloud called the nubecula, which the 
microscope reveals to be made of epithelial debris. In some 
persons a small amount of the waste material of cells from the 
mucous lining of the bladder and other parts of the urinary tract 
may occur, and have no significance. A large amount with mucus, 
or still more with pus, would indicate catarrh of some portion of 
the urinary tract. Practically, the main point to be determined is 
as to whether the cells are from the kidney or not. 

Renal epithelium is spheric, granular, and nucleated, with an 
indistinct cell wall. The coexistence of casts of the uriniferous 



620 



FOODS AND DIGESTION 



tubules would corroborate their testimony as to the existence 
of renal desquamation. Cells from extrarenal parts are distinct, 




Fig. 105. — Epithelium from the urine: a, b, Epithelium from the bladder, from the pelvis of the 
kidney; c, caudate epithelium (pelvis of the kidney?); d, renal epithelium partly changed into fat 
(Vierordt). Greatly magnified. 

nucleated, and flattened, being oval, spindle-shaped, cylindric, or 
tessellated, according to site. Cylindric or caudate cells may be 
derived from the pelvis of 
the kidney, from the prostate 
gland, from Cowper's gland, 
from the urethra, or from 
some parts of the bladder. 
Bladder epithelium is usually 
flat and irregularly oval; 
sometimes desquamation oc- 
curs in patches of cells joined 
at their edges. In the urine 





Fig. 106. — Hyaline casts (narrow and toler- 
ably broad ones). Greatly magnified. 



Fig. 107. — a and c, Waxy casts (Jaksch); b, a cast 
containing crystals of oxalate of lime. Greatly mag- 
nified. 



of women large translucent flat cells from the vagina are nearly 
always present. 

Tube=casts. — As a result of structural mischief in the kidney, 
there are formed in the tubules cylindric casts of coagulable 



THE URINE 



621 



material, which is sometimes fibrin, sometimes mucoid matter, and 
sometimes the plastic substance resulting from the disintegration 
of the cellular lining. Individually they are too small to be seen 
by the naked eye, but in the amount usually collected they appear 
as a light-gray sediment, or perhaps as a cloud at or near the 
bottom of the glass vessel. Under the microscope they are seen 
to be minute cylinders, sometimes glassy, sometimes opaque and 
granular, and sometimes displaying cells. They can be classified 
accordingly as epithelial, hyaline, granular, fatty, and those made 
of blood-disks. If in doubt as to the nature of the material com- 
posing the casts, staining may be restored to. The best results 
are obtained by fixing the sediment to the slide with gentle heat 
and staining the casts with solution of Sudan III. (which detects 

m 





Fig. 108. — Red blood-corpuscles, partly as rings, 
and casts of red blood-corpuscles (Eicbborst). 
Greatly magnified. 



Fig. 109. — Epithelial casts (Jaksch). 
Greatly magnified. 



fatty change) and iodin, which distinguishes the amyloid or 
waxy cast. 

Epithelial casts have opaque spheric renal cells imbedded in 
some plastic matrix. By the number of these one can judge of 
the activity of the desquamative process in cases of nephritis. 
They are usually found in acute nephritis (see Fig. 109 ). 

Hyaline casts are always transparent, and sometimes require 
skilful arrangement of light to show them at all. In case of doubt 
they may be stained with methylene-blue. They can be grouped 
in two subvarietie9> in one of which, the mucous, would be placed 
those that are soft and of delicate outline; in the other, the waxy, 
those that are well defined and brittle. 

The mucous casts alone are sometimes found without any 
other sign of nephritis, and hence must be regarded as not always 




622 FOODS AND DIGESTION 

of serious import. The waxy casts, on the contrary, are never 

found but when the kidneys are diseased (see Figs. 106 and 107). 
Granular casts (Fig. no), as the name indicates, are composed 

of or contain opaque granules which have a yellowish hue. The 

material may be mucoid or waxy, or such 
material as is produced by cellular debris. 
Fatty casts are such as have fat par- 
ticles in the matrix, with or without the 
other bodies mentioned above. If numer- 
ous, they are regarded as evidence of fatty 
change in the kidney. 

Blood casts (Fig. 108) are reddish and 
opaque; they are literally minute clots of 
blood which have taken shape from the 

Fig. no.— Granular casts (jaksch). tubules into which the effusion occurs. 

Greatly magnified. 

I he corpuscles may be so packed as to 
be pressed out of their biconcave shape and appear as reddish 
circles. 

Practical Import. — It has been stated under previous sections 
that if albuminuria or hematuria or an epithelial deposit be of 
renal origin, careful search of several portions of the deposit with 
the microscope will most likely find tube-casts. It occasionally 
happens in cases of Bright's disease that the albuminuria will dis- 
appear, and still the casts can be found in the urine. Hence much 
importance is attached to them in renal diagnosis. As regards 
the significance of particular varieties, it must be noted that if the 
mucous cast alone be present, it does not prove nephritis, but any 
of the other varieties would do so. 

It often happens that several varieties occur in the same sam- 
ple: this probably denotes that the lesion is at different stages in 
different parts of the organ. 

Cystin. — This substance contains sulphur, the composition 
being expressed by the formula C 6 H 12 N 2 S 2 4 . One product of its 
decomposition is the gas hydrogen sulphid; hence a test for it is 
to boil the suspected material with a solution of lead oxid in sodium 
hydroxid. If cystin be present, it will form a black precipitate of 
lead sulphid. As it is very sparingly soluble in water, any con- 
siderable amount in the urine would not remain in solution, but 
be deposited. The deposit is usually abundant, light, and to the 
naked eye resembles amorphous urates. Unlike urates, it is not 
dissolved by heat, though it is soluble in ammonia and also in the 
vegetable acids. When a drop of the ammonia solution is exposed 
uncovered on a glass slide, it deposits crystals which the microscope 
shows to have the form of hexagonal tablets (Fig. 84). 

The extensive use of iodoform for surgical dressings has been 



THE URINE 



623 



the source of a fallacy. The crystals of iodoform, accidentally 
mixed with the urine and viewed by the microscope, will present 
hexagonal tablets not unlike those of cystin. The chemical re- 
action is wholly different, and the pronounced odor of iodoform 
should at once excite suspicion. 

Practical Import. — Cystin exists in the protein molecule as 
a preformed group which is liberated in the tissues and destined 
to be further decomposed. Certain rare individuals and families, 
from causes not ascertained, have the anomaly of metabolism 
which results in a failure to break down the cystin and leads to its 
appearance in the urine. When present there, it is usually in con- 
siderable quantities. Patients do not apparently suffer in health, 
but the deposited cystin eventually forms a concretion in the 
bladder. 

Leucin and Tyrosin. — These two substances are considered 
together, because they are by-products of the same processes of 




Fig. hi. — Leucin and tyrosin (Laache). 



digestion, and when from disease certain biliary matters appear 
in the urine, these can be found also. Tyrosin is recognized by 
its turning red when boiled with Millon's reagent of mercuric 
nitrate; when another portion is carefully warmed with sulphuric 
acid and then treated with a drop of ferric chlorid, it yields a 
violet color. In the urine tyrosin may be in solution or it may 
be thrown down spontaneously as a greenish-yellow deposit. The 
microscope will resolve this deposit into bundles of yellow acicular 
needles in radiating stars, crosses, or sheaves (p. 525). 

Leucin, being more soluble, is less apt to form a spontaneous 
deposit, but if a few drops of the suspected urine are allowed to 



624 FOODS AND DIGESTION 

evaporate by exposure on a glass slide, both leucin and tyrosin 
will appear in the residuum. Under the microscope leucin is 
recognized as greenish-yellow globes with concentric markings or 
radiating spines. If the deposit be touched with a drop of nitric 
acid, cautiously evaporated to dryness, and then moistened with 
sodium hydroxid, the leucin residue will turn yellow or brown 
(p. 499)- 

Practical Import. — These two bodies are found with icterus in 
certain maladies when the liver is seriously involved, as in acute 
yellow atrophy of the liver, phosphorus-poisoning, typhoid, and 
yellow fever. 

Spermatozoa. — These bodies, if present in considerable number 
in the urine, form a whitish cloud. When taken up with the pipet, 
the sperm detaches as a thready, drop-like, viscid mucus. When 
only a few are present, they impart no marked naked-eye property, 
and in looking for them with the microscope, unless a proper 
oblique light be used, they may escape observation. In the urine 
they lose at once their vibratile motion, and yet for days retain 
their structural characters, the small, transparent oval body or 
head with the very attenuated cilium, the whole being only -q^-q in. 
long. 

Practical Import. — Before drawing conclusions as to their 
significance, it must be ascertained if the sample containing them 
be not the first micturition after coitus. If not, they may be the 
washing out of the remains of a nocturnal emission of semen. 
Their only important relation is as an indication of spermator- 
rhea — i. e., the escape of sperm independent of the sexual act 
occurring during the waking hours. 

Pneumaturia. — It is a very rare symptom for the last portion 
of urine to be accompanied by the passage of air from the urethra. 
This is sometimes associated with tympany of the bladder and 
may be the result of accidental introduction of air during irriga- 
tion of the bladder or as the result of knee-breast position for ex- 
amination of the bladder. Another group of cases is due to an 
organism, like the Bacterium lactis aerogenes, which develops an 
odorless gas, usually hydrogen. A third group includes those in 
which there is a fistulous opening, admitting gas from the rectum 
and from abscesses. 

Micro=organisms. — As it is a fluid containing more or less 
organic matter in solution, the urine is a fertile medium for the 
development of microscopic vegetation. The spores or germs 
of these minute plants come from the containing vessels or from 
the dust that floats in the air. 

The common molds, such as penicillium, appear in a few days 
on a stale urine. They are seen microscopically as minute jointed 






THE URINE 625 

threads matted together in a mycelium. Saccharine urine fur- 
nishes the soil for the growth of the yeast fungus, Saccharomyces 
cerevisice, the spores of which may be derived from the floating 
dust of the air. It may be of value as corroborating other evi- 
dence of the presence of sugar. The latter plant is recognized 
as oval cells with granular contents and nuclei multiplying mainly 
by buds, but sometimes by spore-bearing stems. Even before 
discharge the sarcinae of the bladder will reproduce in the urine, 
and be the cause of obscure vesical symptoms. Their microscopic 
structure is peculiar from the cubic form of the little masses made 
by the reproduction of the more minute round particles. The 
bacteria of putrefaction, the Micrococcus urea, vibriones, and other 
similar organisms will flourish not only in the urine outside, but 
even before micturition. They are identified as extremely minute 
rods or granules, single or threaded, still or vibratory. 

Staining. — With a pipet a small drop of the sediment is trans- 
ferred to the slide and spread in a thin film. To fix the cells and 
organisms the film may be set aside to dry spontaneously or be 
heated over a flame cautiously for three minutes, keeping the heat 
of the slide below a point painful to the skin of the hand. When 
dry, it is bathed in a few drops of solution of carbol fuchsin, which 
stains bacteria and tissue-cells. Heat is again applied and the 
film again stained by applying for three minutes Gabbet's blue 
solution, wmich makes most pathogenic organisms blue, but leaves 
the tubercle bacilli red. 

When the gonococcus is sought, the first stain to be used must 
be eosin and the second methylene-blue. 

Practical Import of the Bacteria. — A highly important signifi- 
cance of bacteria in the urine depends upon the fact of their causing 
decomposition of the urea while still in the bladder. If the ammo- 
niacal products be detained in the bladder, they are very apt to 
cause cystitis. It is of the greatest importance to guard against 
the introduction of their germs by means of unsterilized instru- 
ments, such as catheters and sounds. It is possible for them to 
get access to the urine in the bladder from the purulent discharges 
of a deep-seated gonorrhea or gleet. In paralysis of the bladder 
they appear to have the power of spontaneous entrance. In that 
event the harm they may do must be obviated, as far as possible, 
by frequent and thorough evacuations of the bladder and washings 
with antiseptic fluids. 

When the specific pathogenic bacteria are looked for, it must 
be with high-power immersion lenses and substage condensers 
after drying and staining the residue by the approved methods of 
bacteriology. 

It must be noted that the urine in passing through the urethra 
40 



626 FOODS AND DIGESTION 

of healthy subjects may wash out micro-organisms that colonize 
there. Among these is mentioned a diplococcus resembling the 
gonococcus of gonorrhea in all respects save that it is not found 
in pus-corpuscles, a large streptococcus, and even a bacillus which 
neither by form nor by staining can be distinguished from the 
tubercle bacillus. The doubtful bacillus is usually seen singly, 
whereas the bacilli coming from ulcerating urogenital tuberculosis 
are generally in groups or crowds considerable in number, like 
those of a pure culture (Fig. 112). Inoculation experiments would 
serve to distinguish them from the non-tubercular bacilli. The 
coexistence of hectic fever and wasting with pyuria and masses of 
these bacilli in the sediment would prove highly confirmatory of 
their tubercular origin. 








Fig. 112. — Pure culture of tubercle bacilli in the urine in tuberculosis of the genito-urinary appar- 
atus (Zeiss's homogeneous immersion x 1 ^; eye-piece No. 4; drawn with a camera lucida; magnified 
about 1 100) (Vierordt). 

When the pathogenic bacteria are made out in the sediment 
unmistakably by form and number, they point to the specific associ- 
ated disease — the tubercle bacilli to miliary tuberculosis, the 
erysipelas cocci to erysipelatous nephritis, the pus micrococci to 
pyemia or endocarditis, the gonococcus to gonorrhea. 

The hooklets of echinococcus may be found in the urine, denot- 
ing the presence of hydatid cysts somewhere in or about the urinary 
apparatus. Other parasites occasionally seen in the urine of 
persons who have lived in the tropics are Distoma h&matobium, 
Strongylus gigas, and Filar ia sanguinis. 

Ehrlich's Typhoid Diazo-reaction. 1 — In 95 per cent, of the 

1 Artificial diazo-urine for students' practice may be made by adding to 10 c.c. 
of urine i c.c. of a solution of alpha-naphthylamin (o.i gm. in 10 c.c. of water and 
5 c.c. of hydrochloric acid). 



THE URINE 627 

cases of typhoid fever an unknown chromogen appears in the 
urine, which develops a red color under the conditions of the follow- 
ing test: Two solutions are made up and kept in separate bottles; 
one contains 1 gm. of sulphanilic acid dissolved in water 95 c.c., 
with hydrochloric acid, 5 c.c. The other is 0.5 gm. of sodium 
nitrite in 100 c.c. of water. The test is made by mixing \ c.c. of 
the sodium nitrite with 50 c.c. of the sulphanilic-acid solution, and 
to a suitable amount adding an equal volume of the urine. The 
two are shaken together and ammonium hydrate is cautiously 
poured in to overlay the mixture. At the line of contact normal 
urine will appear more or less orange, while pathologic urine gives 
a garnet red. The red color will color the foam when the mixture 
is shaken, and if the test-tube be emptied into a basin of water, 
a salmon color is produced (Plate 8, Fig. 12). 

Practical Import. — This reaction is commonly present in typhoid 
fever, is rarely absent in septicemia, and has been frequently ob- 
served in tuberculosis. 

Fallacy. — A similar reaction occurs from the presence of sali- 
cylic acid, phenacetin, antipyrin, and other aromatic compounds, 
as the result of their administration. 

They must be excluded from the regimen of the patient before 
the test can be regarded as significant. 

Urinary Concretions. — In four-fifths of the cases urinary con- 
cretions are composed of uric acid and urates. Calcium oxalate, 
or mulberry calculi, stand next in the frequency. The rarer primary 
varieties are blood concretions, cystin, xanthin, calcium phosphate, 
calcium carbonate. Secondary to any of these there occurs at 
the last stage in the history of a calculus a deposit of mixed phos- 
phates. These form a white crust, precipitated upon the calculus 
as a result of ammoniacal decomposition in the urine changing the 
reaction and making the phosphates insoluble. 

A concretion should be sawed through the middle, so as to expose 
its concentric layers. A small portion of each distinct layer may 
be examined by the following procedures: 

Calcine a portion of the powder on platinum foil in a Bunsen 
burner or blowpipe flame: 

A. It chars and leaves but little ash = (uric acid, urates, cystin, 
xanthin, blood). 

It gives murexid reaction = (uric acid or urates). 
It dissolves in boiling water = (urates). 
It does not dissolve in boiling water = (uric acid). 
Cystin and xanthin are very rare; the first can be recognized 
by its test given in another place. 

B. It chars very slightly and leaves very much ash = (phos- 
phates, oxalate, or carbonate of calcium). 



628 FOODS AND DIGESTION 

i. Test a fresh portion with dilute hydrochloric acid. It is 
soluble with effervescence = (carbonates are present). It is sol- 
uble without effervescence = (phosphates or calcium oxalate). 

2. Test a fresh portion with acetic acid. It is soluble without, 
effervescence = (phosphatic); it fuses into a bead on platinum 
foil = (mixed phosphates); it does not fuse = (calcium phosphate); 
it is insoluble = (calcium oxalate, which, when calcined on plati- 
num, leaves an ash that turns red litmus blue, or effervesces with 
HC1). 



NDEX 



Absorption, 96 
Acetaldehyd, 409 
Acetamid, 495 
Acetamidophenol, 469 
Acetanilid, 47S 
Acetic acid, 417, 553 

aldehyd, 409 

ether, 433 
Acetone, 413, 426, 607 
Acetonuria, 413, 607 
Acetphenetidin, 479 
Acetyl, 417 
Acetylene, 383, 447 

series, 382 
Achlorhydria, 547 
Achroodextrin, 441, 543 
Acid, acetic, 409, 417, 418, 444, 553 

acetylsalicylic, 469 

amido-acetic, 499 

amino -acetic, 499 

aminocaproic, 499 

aminoglutaric, 499 

aminopropionic, 499 

aminovaleric, 499 

antimonious, 292 

arsenic, 286 

arsenous, 266 

aspartic, 525 

benzoic, 465 

beta-oxy butyric, 422, 607 

boric, 208 

bromic, 144 

butyric, 417, 420, 444, 553 

cacodylic, 287 

capric, 417 

caproic, 417 

caprylic, 417 

carbamic, 235 

carbolic, 454 

carbonic, 103, 191 

chloracetic, 420 

chloric, 140 

chlorous, 140 

cholalic, 538 

cholic, 558 

chromic, 351 

citric, 425 

cresylic, 460 

cyanic, 199 

dextrolactic, 422 



Acid, diacetic, 426, 607 
diaminocaproic, 499 
diaminovaleric, 499 
dithionic, 168 
ethyl-sulphuric, 430 
formic, 417 
gallic, 470 
glacial acetic, 409 
phosphoric, 189 
gluconic, 436 
glutamic, 421, 525 
glutaric, 421 
glycocholic, 558 
glycolic, 421 
glycuronic, 436, 607 
hippuric, 465, 499, 579 
homogentisic, 582 
hydriodic, 147 
hydrobromic, 144 
hydrochloric, 122, 135, 546, 550 
hydrocyanic, 194 
hydroferricyanic, 345 
hydroferrocyanic, 344 
hydrofluoric, 148 
hydrosulphurous, 168 
hypobromous, 144 
hypochlorous, 140 
hyponitric, 177 
hyponitrous, 175 
hypophosphorous, 191 
hyposulphurous, 168 
iodic, 147 
isosuccinic, 421 
kinic, 508 

lactic, 422, 444, 546, 552 
manganic, 348 
margaric, 420 
meconic, 512 
melissic, 409 
metaphosphoric, 189 
molybdic, 187, 189, 362 
muriatic, 135 
myronic, 443, 539 
nicotinic, 505 
nitric, 169 

nitro-hydrochloric, 173 
nitro-muriatic, 173 
nitrous, 175 
nucleic, 532 
oleic, 421 

629 



630 



INDEX 



Acid, orthophosphoric, 190 

oxalic, 200, 421 

oxyacetic, 498 

oxy butyric, 422 

palmitic, 417, 420, 426 

paralactic, 422 

pentathionic, 168 

perbromic, 144 

perchloric, 140 

periodic, 148 

permanganic, 348 

persulphuric, 168 

phenol-sulphonic, 458 

phospho-molybdic, 362 

phosphoric, 189 

phosphorous, 190 

phthalic, 466 

picric, 458 

propionic, 417 

proteins, 551 

prussic, 194 

pyrogallic, 462 

pyrophosphoric, 190 

pyrosulphuric, 168 

pyrotartaric, 421 

quinic, 508 

quinotannic, 508 

racemic, 423 

saccharic, 436 

salicylic, 467 

salicyl-sulphonic, 470 

sarco-lactic, 422 

silicic, 206 

sozolic, 458 

stannic, 298 

stearic, 417, 420, 427 

succinic, 421 

sulphanilic, 567 

sulphobenzoic, 482 

sulphocarbolic, 458 

sulphocyanic, 199, 345 

sulphonic, 415, 430 

sulphovinic, 430 

sulphuric, 160 

sulphurous, 158 

sulphydric, 156 

tannic, 470 

tartaric, 423 

taurocholic, 558 

tetrathionic, 168 

thiocyanic, 200, 345 

thiosulphuric, 168 

trichloracetic, 420 

trithionic, 168 

uric, 488, 579 

uroleucic, 582 

valeric, 417, 420 

xantho-proteic, 458 
Acidimetry, 124, 550, 584 
Acidosis, 423, 608 
Acids, 123, 129, 137, 372 

amido-, 494, 498, 525, 535 



Acids, amino-, 494, 498, 525, 535 

aromatic, 454, 485 

biliary, 558 

definitions of, 123 

detection of, 123 

dibasic, 162 

fatty, 417 

free mineral, 139, 551 

hydroxy-, 454, 485 

ketone-, 426 

monobasic, 162 

nomenclature of, 140 

organic, 372, 421, 552 

oxy-, 139, 144, 147, 168 

strength of, 133 

sulphonic, 430 

thio-, 414 
Acid-salts, 162 
Aconitin, 521 
Acrolein, 402 
Actinic waves, 58 
Adamkiewicz's reaction, 500, 526 
Adenase, 539 
Adenin, 490, 491, 539 
Adeps lanas, 558 
Adrenalin, 461 
/Ether, 403 

universal, 17, 58 
Affinity, chemical, 62, 70 
Agaric, 517, 519 
Agglutinins, 522 
Aggregates, 93 
Air, composition of, 105 

liquid, 108 
Alabaster, 241 
Alanin, 499, 525 
Albumen, 524, 527 
Albumin, 524, 527 

digestion of, 554 

in urine, 609 

nucleo-, 532 

serum-, 524, 609 
Albuminates, 530 
Albuminoids, 524 
Albuminous substances, 524 

analytical reactions of, 526 
Albumins, 527 
Albumoses, 533 
Albumosuria, 556 
Alcohol, 392, 395 

absolute, 395 

amyl, 399 

benzyl, 453, 463 

butyl, 399 

denatured, 393, 395 

diluted, 395 

ethyl, 395 

methyl, 392 

tests for, 392 
Alcoholic liquors, 397 
Alcohols, 371, 392, 399 

aromatic, 453, 463 



INDEX 



631 



Alcohols, constitution of, 392, 394 
diatomic, 399 

dihydric, 399 

monatomic, 399 

primary, 400 

secondary, 400 

tertiary, 400 

triatomic, 399 

trihydric, 399 
Aldehyd, acetic, 406 

ammonia, 407 

benz-, 464 

par-, 410 
Aldehyds, 406 
Aldol, 410 
Aldoses, 434 
Ale, 397 

Aliphatic compounds, 371, 372 
Alizarin, 474, 551 

sodium sulphonate, 474, 551 
Alkali metals, 211, 236 
Alkalimetry, 127 
Alkaline earths, 236 
Alkalis, 125, 211 
Alkaloids, 501, 521 

antidotes to, 503 

cadaveric, 517, 521 

classification, 503 

detection of, 503, 522 

extraction of, 502 

separation from tissue, 521 
Alkaptonuria, 582 
Alkylanilin, 476 
Alkyl radicals, 417 
Allantoin, 494 
Allotropic modifications, 76 
Alloxan, 489, 490 
Alloxuric bases, 489 
Alloy, definition of, 210 
Allylene, 382 
Almen's test, 617 
Alum, 254 
Alumina, 253 
Aluminium, 251 

analytical reactions of, 255 

and ammonium sulphate, 254 

and potassium sulphate, 254 

chlorid, 253 

hydroxid, 252 

naphthol-disulphonate, 473 

oxid, 253 

sulphate, 253 
Alumnol, 473 
Amalgam, 210, 306 

ammonium, 231 

tin-, 298 
Amanitin, 519 
Amaranth, red, 477 
Amido-acetic acid, 498 

-acids. See Amino-acids. 

benzene, 476 

compounds, 476 



Amido-diacids, 525 

-phenol, 478, 479 

-phenyl, 476 
Amidogen, 494 
Amids, 372, 494 
Amin, diphenyl-, 471 

ethyl-, 497 

methyl-, 497 

propyl-, 497 
Amino-acetic acid, 499 
Amino-acids, 494, 498, 525, 535 
Amino-compounds, 476 
Amins, 372, 494, 497 
Ammonia, 231, 525 

derivatives, 494 

liniment, 233 

substituted, 494 

water, 232 

toxicology of, 233 

fatal dose and period, 233 
postmortem appearances, 234 
symptoms, 233 
tests for, 235 
treatment, 233 
Ammoniated mercury, 313 
Ammonio-copper compounds, 302 

-magnesium phosphate, 189, 578, 586 

-nitrate of silver, 275 
Ammonium, 231 

acetate, 234 

amalgam, 231 

benzoate, 465 

bicarbonate, 235 

carbamate, 235, 492, 535 

carbonate, 233, 234, 492, 535, 578, 585 

chlorid, 234 

cyanate, 200 

derivatives, 494 

formate, 195 

hydroxid, 232 

lactate, 492, 535 

molybdate, 189, 362 

nitrate, 234 

phosphate, 235 

-magnesium phosphate, 189, 578, 586 

-sodium phosphate, 235 

sulphid, 235 

sulphydrate, 235 

urate, 600 

valerate, 417 
Amorphism, 152 
Amorphous phosphorus, 178 
Ampere, 49 

Amphoteric reaction, 498 
Amygdalin, 194, 443, 464, 539 
Amyl alcohol, 399 

nitrite, 431 
Amylamin, 517 
Amylases, 537, 543, 556 
Amylene, 381 

hydrate, 381 
Amylodextrin, 441 



632 



INDEX 



Amyloid degeneration, 531 

substance, 531 
Amylolytic enzyms, 537, 556 
Amylopsin, 556 
Amylum, 440 

iodatum, 146 
Anacidity, 549 
Analysis, definition of, 63, 134 

gas, 84 

gravimetric, 126 

organic, 363 

proximate, 363 

ultimate, 363 

urinary, 522 

volumetric, 126 
Anilid, 478 
Anilin, 476 

dyes, 477 
Animal charcoal, 99 

food, 542 
Anions, 128 
Anisidin, 480 
Anode, 46 

Anthracene, 445, 474 
Anthracite coal, 98 
Anthraquinon, 474 
Antibodies, 523, 563 
Antidotes to acids, 138, 165, 171, 203 

alkalis, 215 

alkaloids, 503 

antimony, 294 

arsenic, 270 

barium, 246 

carbolic acid, 456 

copper, 304 

cyanids, 196 

hydrocyanic acid, 196 

lead, 324 

mercury, 315 

nitric acid, 171 

oxalic acid, 203 

phosphorus, 181 

silv:.'., 336 

sulphuric acid, 165 

zinc, 356 
Antifebrin, 478 
Antimonious chlorid, 292 

oxid, 292 
Antimony, 291 

antidotes to, 294 

black, 291 

butter, 292 

chlorid, 292 

crude, 291 

oxid, 292 

potassium tartrate, 292 

sulphid, 291, 294 

sulphurated, 291 

terhydrid, 292 

toxicology, 292 

chronic poisoning from, 293 
detection of, 296 



Antimony, toxicology, fatal dose of, 293 
period of, 293 

postmortem appearances, 294 
quantitative estimation of, 297. 
symptoms of, 293 
tests for, 294 
treatment of, 294 
trichlorid, 292 
trioxid, 292 
Antipyrin, 481 

toxicology of, 482 
Antiseptics, 458, 460 
Antitoxins, 522 
Anuria, 580 
Apomorphin, 513 

Apothecaries' weights and measures, J9 
Aqua, 85 

acidi carbonici, 103 
ammonia, 233 
chlori, 120 • 
destillata, 85 
fortis, 169 

hydrogenii dioxidi, 88 
regia, 173 
Aqueous vapor, 40, 85 

tension of, 40 
Arabinose, 437 
Arecolin, 503 
Argentum, 333 
Arginin, 525, 527 
Argol, 423 
Argon, 98 
Aristol, 453 _ 
Aromatic acids, 464 
alcohols, 462 
amido-compounds, 476 
compounds, 476 
series, 445 
Arsenic, 263 
acid, 286 
antidotes to, 269 

detection of, in case of poisoning, 282 
eating, 273 
oxids, 266, 286 
sulphids, 290 
terhydrid, 265 
toxicology, 266 

cadaveric imbibition of, 291 
chronic poisoning from, 270 
detection of, in gastric contents and 

viscera, 282 
distribution of, in system, 285 
fatal dose of, 269 

period of, 269 
in air, 288 
in anilin dyes, 288 
in beer, 288 
in cleaners, 28" 
in household articles, 288 
in king's yellow, 290 
in medicinal preparations, 267, 280 
in orpiment, 290 



INDEX 



£>33 



Arsenic in Paris green, 290 

in preservatives, 2S7 

in realgar, 290 

in Scheele's green, 290 

in soil, 291 

in urine, 289 

in wall-paper, 2S4 

medical uses of, 264, 272 

normal, 285 

pentoxid, 286 

physiologic effects of, 265 

postmortem appearances after, 270 

quantitative determination of, 284 

symptoms of poisoning from, 2 68 

tests for, in complex solutions, 276 
in simple solutions, 275 
in solid form, 273 

treatment in poisoning by, 269 

trichlorid, 265 

trioxid, 266 

trisulphid, 273 

white, 266 
Arsenic-eating, 273 
Arseniuretted hydrogen, 265 
.Arsenous acid, 266 

anhydrid, 266 

iodid, 287 

oxid, 266 
Arsin, 265 
Asbestos, 242 
Aseptol, 458 
Ash, bone, 241 
Aspartic acid, 498, 525, 535 
Aspirin, 469 
Astral oil, 379 
Atmospheric air, 105 

pressure, 106 
Atom, definition of, 109, 111 
Atomic theory, 109 

weights, determination of, no 
Atomicity, 114 
Atoms, 76, 109, 250 

quanti valence of, 114, 251 
Atoxyl. ::- 
Atropin, 503, 506 

and ptomains, 517 

aromatic test for, 507 

in morphin and opium poisonin 

postmortem appearances after. 507 
separation from tissue, 517 
symptoms of poisoning by. 507 
tests for, 507 
treatment of poisoning from, 507 

Auric chlorid, 359 
sulphid, 359 

Aurum, 358 

Autolytic enzyms, 539 

Avogadro's law, 77, 95 

Azins, 4S1 

Azoturia, 581 

Azurite, 300 



Bacteria, pathogenic, 500, 517 
death point of, 567 
in milk, 567 
in stomach, 546 
in urine, 565 
Baking powders, 227, 235 
Balance, iS 
Balsams. 452 
Barite. 245 
Barium, 245 

antidotes to, 246 

carbonate, 246 

chlorid, 246 

chromate, 247 

dioxid, 66 

hydroxid, 245 

nitrate, 246 

oxid, 236, 245 

sulphate, 246 

tests for, 247 
Barley sugar, 438 
Barometer, 107 
Baryta, 236, 245 
Bases, definition of, 124, 129 
Basharns mixture, 346 
Batter\% galvanic, 48 
Beckmann's apparatus for cryoscopy, 3S 

for determining boiling point, 369 
Beer, 397 
Beet-sugar, 438 
Belladonin, 506 
Bell-metal, 301 
Bence-Jones 1 protein, 616 
Benzaldehyd, 464 
Benzene, 445, 446 

hydroxids, 453 

nucleus, 44S 

series, 445, 446 

test, 617 
Benzidin, 483 
Benzin, 379 
j Benzoic acid. 465, 569 

sulphinid, 4S2 
Benzoin, 465 
Benzol, 446 
Benzo-pyrrole, 486 
Benzoyl chlorid, 466 

sulphonic imid, 482 
Benzyl alcohol, 463 

amin, 476 
Benzyl -glycocol, 465, 499 
Beryllium, 117 
Betain, 517 
Betelnut, 503 
Betol, 473^ 

Bettendorff's test. 275 
Bicarbonate of potassium, 220 

sodium, 22S 
Bichlorid of mercury-, 309 
Bichromate of potassium, 351 
Bile, 5 

detection of, in urine, 618 



634 

Biliary acids, 558, 618 

calculi, 559 

pigments, 559, 618 
Bilirubin, 559 
Biliverdin, 559 
Biologic test, 563 
Bismuth, 330 

carbonate, 330 

citrate, 331 

hydroxid, 330 

nitrate, 331 

oxid, 330 

oxy-salts, 330 

subcarbonate, 330 

subnitrate, 331 
arsenic in, 287 

sulphid, 332 
Bismuthyl, 330 

carbonate, 330 

nitrate, 331 
Bisulphid of carbon, 193 
Biuret reaction, 496, 526, 554 
Black antimony, 291 

-lead, 98 

oxid of copper, 302 
of manganese, 348 
mercury, 308 

-wash, 308 
Bleaching-powder, 140 
Blood, 561 

coloring-matter, 529 

corpuscles, 561 

detection of, 564 

in urine, 616 

fibrin, 562 

phagocytes, 562 

plasma, 562 

platelets, 562 

-serum, 562 

-stains, examinations of, 564 
Blow-pipe, 114 
Blue mass, 307 

pill, 307 

Prussian, 345 

-stone, 303 

Turnbull's, 345 

vitriol, 303 
Boas' test, 549 
Boiling point, 41, 369 

test, 551 
Bone, 241 

-ash, 241 

-black, 99 

-oil, 483 
Borax, 209 

bead, 208 

detection of, 209, 568 
Boric acid, 208 

test for, 209, 568 
toxicology of, 209, 568 
Boron, 208 

trioxid, 208 



INDEX 



Bottger's bismuth test, 546 

Botulism, 520 

Boyle's law, 107 

Brandy, 397 

Brass, 301 

Bread, alum in, 255 

soda, 228 
Brimstone, 150 
Brittleness, 29 
Bromates, 144 
Brombenzenes, 449 
Bromic acid, 144 
Bromid-gelatin process, 335 
Bromids, analytical reactions of, 144 
Bromin, 142 

detection of, 143 

fatal dose, 143 

symptoms of poisoning from, 143 

treatment of poisoning from, 143 

water, 142 
Bromism, 144 
Bromoform, 391 
Bronze, 301 
Brucin, 511 

separation from tissues, etc., 521 

symptoms of poisoning by, 512 

tests for, 512 

toxicology, 512 
Bunsen burner, 114 
Burets, 124 

Burnett's disinfectant, 355 
Butane, 375, 376 
Butene, 381 
Butter, 420, 428, 565 

of antimony, 292 
Butterine, 428 
Buttermilk, 565 
Butylamin, 517 
Butylene, 381 

Butyric acid, 420, 428, 553 
Butyrin, 420, 428 



Cacodyl, 287 
Cacodylate of sodium, 287 
Cacodylic acid, 287 
Cadaveric alkaloids, 517 
Cadaverin, 500, 517 
Cadmium, 117 

sulphid, 276 
Cassium, 117 
Caffein, 490, 491 
Calcined magnesia, 243 
Calcium, 237 

analytical reactions of, 242 

carbid, 239, 383 

carbonate, 240 

chlorid, 238 

fluorid, 148 

hydroxid, 237 

hypochlorite, 239 

oxalate, 203, 591 



INDEX 



6 35 



Calcium oxid, 237 
phosphate, 241 
sulphate, 241 
sulphid, 239 
superphosphate, 241 
Calc-spar, 58 
Calculi, biliary, 558 

urinary, 536 
Calomel, 309 
Calorie, 34, 73, 541 
Calorimeter, 34, 541 
Calx, 237 

chlorinata, 140 
sulphurata, 239 
Camphor, 453 
Cane-sugar, 437 
Caramel, 438 
Carbamid, 494 
Carbanion, 192 
Carbazotic acid, 452 
Carbinols, 463 
Carbo animalis, 99 
purificatus, 99 
ligni, 99 
Carbohydrates, 372, 433 

in the body, 443 
Carbolic acid, 445, 454 
antidotes to, 456 
symptoms of poisoning by, 455 
tests for, 457 
toxicology, 455 
Carboloferric test, 457, 552 
Carbon, 98 
bisulphid, 193 
circulation of, 104 
compounds, 371 
dioxid, 102 
in blood, 562 
toxicology, 106 
symptoms of, 106 
tests for, 106 
treatment in, 106 
disulphid, 193 
monoxid, 100 

hemoglobin, spectrum of, 101, 531 
in smokeless fuel, 10 1 
postmortem appearances after, 10 1 
simple tests for, 10 1 
symptoms in poisoning by, 101 
tests for, 10 1 
toxicology, 10 1 

treatment in poisoning by, 10 1 
tetrachlorid, 389 
Carbonates, analytical reactions of, 103 
Carbonic acid, 103 
diamid, 193 
oxid, 10 1 
Carbonyl, 192, 385 
chlorid, 192, 386, 388 
diamid, 193 
Carborundum, 207 
Carboxyl, 385, 417 



Carbylamin, 498 
Carnalite, 212, 215, 241 
Casein, 528, 565, 566 
Caseinogen, 528, 565 
Caseose, 533 
Cast-iron, 337 
Casts, urinary, 620 
Catalases, 538, 563, 567 
Catalyser, retarding, 195 
Catalysis, 87, 536 
Cathode, 46 

rays, 53 
Cations, 128 
Caustic, 335 

lunar, 335 

potash, 213 

soda, 224 
Celestite, 245 
Cell, dry, 47 

galvanic, 47 

Grenet, 47 

Leclanche, 47 
Celluloid, 443 
Cellulose, 442 

nitro-, 443 
Centigrade thermometer, 31 
Centrifuge, 577 

tests for milk, 574 
for urine, 577 
Cerium, 361 

oxalate, 361 
Cesium, 231 
Cevadin, 515 
Chains, 371, 448 

closed, 448 

open, 371 
Chalk, 237, 238 
Chalybeate waters, 85, 256 
Charcoal, 99 

animal, 99 
Charles' law, 107 
Cheese, 528, 565 
Chemical action, definition of, 62 

affinity, 62, 69 

divisibility, 109 

energy, 69 

equations, 70 

formulas, 112 

philosophy, 108 

reactions, 112 

symbol, definition of, 112 
Chemistry, analytical, 134 

definition of, 62 

inorganic, 62 

organic, 62, 363 
Chili saltpetre, 225 
Chinolin, 488 
Chloracetic acids, 420 
Chloral, 410 

amid, 497 

formamid, 497 

hydrate, 411 



6 3 6 



INDEX 



Chloral, toxicology, 411 

cases of poisoning by, 411 
estimation of, 412 
fatal dose of, 412 
isolation of, 412 
physiologic action, 411 
postmortem appearances after, 411 
symptoms in poisoning by, 411 
tests for, 412 

treatment in poisoning by, 411 
Chloranion, 131, 140 
Chlorates, analytical reactions of, 141 
Chloric acid, 140 

oxids, 139 
Chlorid of lime, 119, 140 
Chloridion, 131 

Chlorids, analytical reactions of, 131 
Chlorin, 118 

acids, 140 

and hydrogen, 121 

family, 149 

oxids, 139 

toxicology of, 121 

water, 120 
Chlorinated lime, 119, 140 
Chlorodyn, 512 
Chloroform, 384 ; 

as solvent of alkaloids, 521 

cases of poisoning by, 387 

fatal dose of, 387 
period of, 387 

isolation of, 389 

physiologic action of, 387 

postmortem appearances after, 387 

properties of, 386 

symptoms in poisoning by, 387 

tests for, 388 

treatment in poisoning by, 387 
Chlorous acid, 140 

oxid, 139 

tetroxid, 139 
Chocolate, 490 
Choke-damp, 102 
Cholalic acid, 558 
Cholesterin, 558, 559, 560 
Choletelin, 559 
Cholin, 517, 518 
Chondrogen, 528, 531 
Chondroitin, 531 
Chondro-mucoid, 531 
Chondroproteins, 531 
Chromates, analytical reactions of, 352 
Chrome alum, 254 

yellow, 325 
Chromic acid, 351 

hydroxid, 350 

oxid, 350 
Chromium, 350 

green, 350 

ions of, 350 

sulphate, 352 

toxicology, 352 



Chromium, toxicology, fatal dose of, 352 
period of, 352 
postmortem appearances after 

poisoning from, 352 
tests for, 352 
treatment in poisoning from, 352 

trioxid, 351 
Chromoproteins, 527, 529 
Chyluria, 560 
Chyme, 545 
Chymosin, 545 
Cider, 397 

Cinchona alkaloids, 503, 508 
Cinchonidin, 508 
Cinchonin, 508 

sulphate, 509 
Cinnabar, 306 
Citric acid, 425 
Claret, 397 
Classification, 116 
Clay, 251 

Clinical thermometer, 32 
Clotting enzyms, 538, 545 
Coagulases, 538, 545 
Coagulated proteins, 526, 533 
Coagulation, 526, 533, 562 
Coal, 99, 445 

-tar, 445 

dyes that are harmless, 477 
Cobalt, 357 
Cocain, 503, 507 

symptoms of poisoning from, 508 

tests for, 508 

toxicology, 508 
Codamine, 512 
Codein, 512 
Coffee, 490 
Cognac, 397 
Cohesion, 28, 62 
Coin silver, 301 
Coke, 98 
Colchicin, 521 
Collagen, 528 
Collidin, 485, 518 
Collodion, 443 
Colloidal copper, 300 

platinum, 93, 536 

silver, 333 

solutions, 93 
Colloids, 93, 524 
Colonial spirits, 392 
Colostrum, 564 
Columbian spirits, 392 
Columbium, 117 
Combustion, 72 
Common salt, 225 
Complement, 523 
Compound ethers, 417, 430 

radicals, 194, 377 
Compounds, decomposition of, 363 

definition of, 63, n 1 
Concentrated lye, 224 



INDEX 



637 



Congo-red test, 483, 549 
Coniin, 503, 504 

and ptomains, 517 

separation of, from tissue, 517 

symptoms in poisoning from, 504 

tests for, 504 

toxicology, 504 

treatment in poisoning by, 504 
Conjugate proteins, 527, 529 
Cooking soda, 224 
Copper, 300 

acetate, 303 

ammonio-sulphate, 305 

antidotes to, 304 

arsenite, 303 

black oxid, 302 

chlorids, 302 

colloidal, for water purification, 301 

hydroxid, 302 

ions of, 301 

oxid, 302 

pyrites, 300 

subacetate, 303 

sulphate, 303 

sulphid, 305 

tests for, 305 

toxicology, 303 

acute poisoning from, symptoms of, 

3°3 
chronic poisoning from, 304 
distribution of, in nature, 300 
separation of, from animal matter, 
306 
Copperas, 342 
Corindin, 518 
Corpse light, 373 
Corrosive alkalies, 211 

chlorid of mercury, 309 

sublimate, 309 
Corundum, 253 
Cotton, 442 
Coulomb, 49 
Cream, 570, 572 

of tartar, 222 
Creamometer, 570, 572 
Creatin, 493, 535 
Creatinin, 494, 535 
Creolin, 460 
Creosol, 460 
Creosote, 460 
Cresol, 460 
Cresylic acid, 460 
Creta praeparata, 240 
Critical temperature and pressure, 44 
Crookes tube, 54 
Cryolite, 252 
Cryoscopic method, 368 
Cryoscopy of blood, 38 

of urine, 39 
Crystallization, 152 
Crystallography, 152 
Crystalloids, 93 



Cumene, 446, 452 
Cumol, 446, 452 
Cuprammonium, 302 
Cupric acetate, 302 

arsenite, 303 

chlorid, 302 

ferrocyanid, 304 

hydroxid, 302 

oxid, 302 

sulphate, 303 

sulphid, 304 
Cuprite, 300 
Cuprous oxid, 302 
Cuprum, 301 
Curd, 566 
Current electricity, 45 

strength, 49 
Cyanates, 199 
Cyanhydric acid, 194 
Cyanic acid, 199 
Cyanidion, 199 
Cyanids, analytical reactions of, 199 

antidotes to, 199 
Cyanogen, 194 
Cyanuric acid, 492 
Cyclic compounds, 372, 445 
Cymene, 452 
Cy stein, 501 
Cystin, 500, 525, 622 
Cytosin, 490 



D Alton's atomic theory, 109 

laws, 108 
Daturin, 506 
Davy's safety-lamp, 103 
Decay, 37°,. 479 

Decomposition by electricity, 50, 78, 128 
heat, 363 
light, 335 
Deliquescence, 84 
Deodorizers, 140 
Desiccator, 162 
Developers, 335 
De wees' carminative, 244 
Dew-point, 86 
Dextrin, 395, 441 
Dextrorotation, 58 
Dextrose, 434 
Diabetic urine, 444 
Diacetic acid, 426 

ether, 443 
Dialysis, 92 
Dialyzed iron, 341 
Dialyzer, 93 
Diamin, 481, 519 
Diamino-acids, 525 
Diamond, 99 
Diastase, 395, 537, 555 
Diazobenzene sulphate, 481 
Diazo-compounds, 480 
Diazo-reaction in urine, 626 



6 3 8 



INDEX 



Dibasic acids, 162 
Didymium, 117 
Diet, purin-free, 492 
Dietary standards, 542 
Diethylamin, 497 
DifTusates, 93 
Diffusion, 92 

of gases, 92 

of liquids, 92 
Digestion, 540, 542 
Digitalin, 443 
Dihydric phenols, 450, 460 
Dimorphism, 152 
Dionin, 513 
Diphenyl, 451, 471 

-amin, 471 
Dippel's oil, 484 
Disaccharids, 438 
Disinfectants, 140, 157, 406 
Dissociants, 132 
Dissociation, 127 

electrolytic, 95, 128 

hydrolytic, 130, 189, 192, 198, 220, 228 

of a^dibasic acid, 163, 182, 220 

of tribasic acid, 188 
Distillation, 85 

destructive, 392 

fractional, 378 
Disulphid of carbon, 193 
Divisibility, 29 

chemical, 109, 250 
Dolomite, 242 
Donovan's solution, 287 
Double salts, 189, 254 
Dried alum, 254 
Drinking-water, 259 
Ductility, 29 

Dyes, coar-tar, harmless, 477 
Dynamite, 431 



Earths, 251 

alkaline, 223 
Ecgonin, 503, 507 
Efflorescence, 83 
Ehrlich's diazo-reaction, 566 
Elasticity, 29 
Elastin, 528 
Electricity, 45 
Electrodes, 46 
Electrolysis, 50, 78, 128 
Electrolyte, 50, 128 
Electrolytic dissociation, 95, 128 
Electromotive force, 46 

negative bodies, 51, 112 

positive bodies, 51, 112 
Electrons, 46, 54, 63, 109, in, 250 
Element, definition, 63, in 
Elementary analysis, 363 
Elements, 63 

classification of, 117 

derivation of names of, 117 



Elements, metallic, 64 

natural groups of, 117 

non-metallic, 63 

typic, 64 

valence of, 117 
Emanation from radium, 248, 251 
Emerald green, 290 
Emery, 253 

Empirical formulas, 112, 367 
Emulsin, 446, 464, 539 
Emulsion, 428 
Energy, 17, 73 

Joule's unit of, 74 

of alkali metals, 236 

of foods, 539 

of hydrogen dioxid, 87 
Enterokinase, 556, 560 
Enzyms, 396, 535, 567 

classification of, 537 

functions of, 535 

nomenclature, 537 

oxidizing, 567 
Eosin, 462 
Epiguanin, 489 
Epithelium in urine, 560 
Epsom salt, 244 
Equations, chemical, 66, 112 

reversible, 82, 433 
Equilibrium, 82, 433 

of three phases, 43 

reaction of, 37, 83 
Equivalence, 125 
Erbium, 117 
Erepsin, 534,^ 556, 560 
Erythrodextrin, 543 
Erythrosin, red, 477 
Esbach's albuminometer, 553 
Esters, 372, 427, 430, 432 
Ethane, 374, 376 
Ethene, 381 
Ether, 17, 58, 403 

acetic, 433 

ethyl, 403 

nitrous, 430 

sulphuric, 403 

as solvent of alkaloids, 521 
detection of, 405 
fatal dose of, 405 

period of, 405 
postmortem appearances after, 405 
properties of, 404 
symptoms of, 405 
toxicology, 405 

treatment in poisoning by, 405 
Ethereal sulphates, 430, 589 

sulphuric acid, 430, 589 

waves, 58 
Ethers, 371, 402 

compound, 417, 430 

mixed, 402 

simple, 402 
Ethine, 383 



INDEX 



639 



Ethyl acetate, 83, 428, 433 
alcohol, 395 
bromid, 392 
chlorid, 391 
ether, 403 

hydrogen sulphate, 404 
hydroxid, 395 
iodid, 392 
mercaptan, 414 
nitrate, 430 
nitrite, 430 
oxid, 403 
sulphid, 430 
sulphonic acid, 430 
sulphuric acid, 430 
Ethylamin, 497 
Ethylene, 381 
bromid, 392 
glycol, 401 
Ethylic alcohol, 395 

cases of poisoning by, 397 
fatal dose of, 398 

period of, 398 
isolation of, 398 
physiologic action of, 397 
postmortem appearances after poi- 
soning by, 398 
properties of, 397 
symptoms of poisoning by, 397 
tests for, 398 

treatment in poisoning by, 398 
Eucain, 508 
Eucalyptol, 453 
Euchlorhydria, 547 
Eudiometer, 84 
Evaporation, 39 
Exalgin, 479 

Examination, clinical, of gastric con- 
tents, 544 
of milk, 564 
of urine, 576 

Fahrenheit's thermometer, 31 

Farad, 49 

Faraday's laws, 52 

Fats, 426 

Fatty acids, 417 

Fehling's solution, 545 

test, 545 
Feldspar, 212 

Fermentation, 395, 444, 535 
Fermented beverages, 397 
Fermenting power, 557 
Ferments, 395, 444, 535 
Ferratin, 338 
Ferric acetate, 342 

chlorid, 340 

citrate, 344 

hydrate, 270, 341 

hydroxid, 270, 341 

ions, 339 

nitrate, 343 



Ferric oxid, 341 

phosphate, 344 

salts, tests for, 347 

sulphate, 342 

sulphocyanate, 345 

tartrate, 344 
Ferricyanids, 345 
Ferricyanogen, 343 
Ferrocyanidion, 345 
Ferrocyanids, 345 
Ferrocyanogen, 345 
Ferrous carbonate, 343 

chlorid, 340 

-ferric oxid, 341 

hydroxid, 341 

iodid, 342 

ions, 339 

oxid, 341 

phosphate, 344 

salts, test for, 347 

sulphate, 342 

sulphid, 342 
Ferrum, 337 
Feser's lactoscope, 571 
Fibrin, 528, 533, 553, 562 
Fibrinogen, 528, 562 
Filters, 259, 261 

Pasteur, 260 

town, 259 
Fire-damp, 373 
Flame, structure of, 113 

-tests, 222, 239, 241 
Flashing point, 380 
Fleitmann's test, 282 
Flowers of sulphur, 150 
Fluorescein, 89, 461 
Fluorescence, 58 
Fluor in, 148 
Fluorspar, 148 
Food, absorption of, 540 

animal, 540 

energy of, 540 

fats of, 541 

fuel value of, 541 

plants, 540 

-poisoning, 520 

proteins of, 540 
Force, 17, 73, 539 
Formaldehyd, 406, 437, 568 
Formalin, 407, 437, 568 
Formamid, 497 
Formic acid, 406, 409 

aldehyd, 406 
Formin, 498 
Formose, 436 
Formulas, chemical, 112, 367 

constitutional, 115, 370 

empiric, 112, 367 

graphic, 115, 370 

molecular, 112, 367 

rational, 112 

structural, 370 



640 



INDEX 



Fowler's solution, 287 
Fractional distillation, 353 
Fraunhofer's lines, 56 
Freezene, 408, 568 
Freezing mixtures, 37 

point, 35, 96 
Frdhde's reaction, 515, 526 
Fructose, 435, 436 
Fruit essences, 433 
Fruit-sugar, 436 
Fuel oil, 379 
Fusel oil, 396, 399 
Fusing point, 35 



Galactase, 567 
Galactose, 437, 439 
Galena, 320 
Gallic acid, 470 
Gallium, 117, 251 
Gall-stones, 559 
Galvanic cell, 45 

current, 45 
Galvanized iron, 353 
Gas analysis, 84 

definition of, 29 

illuminating, 372, 382 

natural, 378 

tension, 29 
Gasoline, 379 
Gastric acids, 546 

contents, 544 

juice, 544 
Gay Lussac's law, 30, 111 
Gelatin, 528 
Gelsemium, 516 

fatal dose of, 516 
period of, 516 

separation from tissues and organs, 521 

symptoms of poisoning by, 516 

tests for, 516 

toxicology, 516 
Germanium, 117 
German silver, 357 
Germs in milk, 566 

in stomach, 546 
Gin, 397 
Glacial acetic acid, 409 

phosphoric acid, 189 
Glass, 206 
Glauber's salt, 225 
Globin, 527 
Globulin, 527 
Globulose, 533 
Glonoin, 431 
Glucinum, 117 
Gluconic acid, 436 
Glucoproteins, 527, 531 
Glucosamin, 500, 525, 535 
Glucose, 395, 434, 444, 537 
Glucosids, 443, 464, 539 
Glue, 528 



Glutaric acid, 421, 525 
Gluten, 440 
Glycerids, 417 
Glycerin, 401, 427 

arsenic in, 287 

cupric test for glucose, 545 
Glycerites, 402 
Glycerol, 401 
Glyceryl trinitrate, 431 
Glycin, 465, 499 
Glycocholic acid, 421, 499 
Glycocoll, 466, 499, 525, 535 
Glycogen, 441 
Glycols, 401, 421 
Glycoproteins, 531 
Glycosuria, 444 
Glycozone, 86 
Glycuronic acid, 436, 607 
Glyzylalanin, 534 
Gmelin's test, 559, 560, 618 
Gold, 358 

and sodium chlorid, 359 

chlorid, 359 

coin, 358 

sulphid, 359 

tests for, 359 
Goulard's extract, 322 
Graham's law, 92 
Granite, 207 
Grape-sugar, 435 
Graphic formulas, 115, 370 
Graphite, 99 

Gravimetric methods, 126 
Gravitation, 18, 62 
Green, S. F., 477 
Green vitriol, 342 
Guaiac test, 538, 563 
Guaiacol, 461 
Guanase, 539 
Guanidin, 489 
Guanin, 489, 490, 491, 535 
Guaranin, 490 
Gum, 441 

-arabic, 441 

British, 441 . 
Gun-cotton, 443 
Gunpowder, 217 

smokeless, 458 
Giinzburg's test, 549 
Gypsum, 241 



H^MATIN, 529 

Haematoidin, 530 
Haemin, 529, 563 

crystals, 529 
Haemoglobin, 529 
Halogen derivatives of hydrocarbons, 

37!> 384 
Halogens, 149 
Haloids, 149 
Hardness of water, 240 



INDEX 



641 



Harle's solution, 287 
Hartshorn, 232 
Heat, 28 

action upon compounds, 65 
matter, 28 
organic substances, 363 

atomic, 35 

capacity, 34 

decomposition by, 364 

latent, 36 

of decomposition, 73 

of oxidation, 73 

specific, 34 
Heavy magnesia, 243 
Hehner and Richmond's formula, 571 
Hehner's test for formaldehyd, 569 
Helium, 98, 249 
Helleborin, 443 
Heller's test, 610, 617 
He matin, 529 
Hematite, 337 
Hematoidin, 530 
Hematoporphyrin, 530, 581 
Hematuria, 616 
Hemin, 529, 563 
Hemlock, 503, 504 
Hemoglobins, 529 
Hemoglobinuria, 617 
Hemolysin, 524, 563 
Henbane, 503, 506 
Henry's law, 91, 123 
Hepar sulphuris, 219 
Heroin, 513 

Heterocyclic compounds, 448, 483 
Heteroxanthin, 450 
Hexagonal system of crystals, 153 
Hexamethylenamin, 498 
Hexane, 376 
Hexons, 525, 527 
Hexoses, 434 
High wines, 396 
Hippuric acid, 465, 535 
Histidin, 525, 527 
Hoffman's anodyne, 405 
Homatropin, 506 
Homologous series, 377 
Humidity of the air, 85 

relative, 86 
Hydracids, 139 
Hydrargyri oleatum, 309 

massa, 307 

unguentum, 307 
Hydrargyrum, 306 

cum creta, 307 
Hydrastin, 503 
Hydrazin, 481 
Hydrazo-compounds, 481 
Hydrazones, 481 
Hydriodic acid, 147 

ether, 392 
Hydrion, 131 
Hydrobromic acid, 144 

4i 



Hydrobromic ether, 399 
Hydrocarbons, 371, 376 
nomenclature, 377 
saturated, 376 
unsaturated, 381, 382 
Hydrochloric acid, 135 
detection of, 139 
fatal dose, 137 

period, 137 
in gastric contents, 546 
poisoning, postmortem appearances, 

138 
symptoms of, 138 
treatment, 138 
properties of, 136 
test for silver, 136 
tests for, 138 
toxicology, 137 
Hydrocyanic acid, 194 
antidotes to, 196 
cases of poisoning by, 196 
estimation of, 198 
fatal dose, 195 
isolation of, 198 
physiologic action of, 196 
postmortem findings after, 197 
properties of, 195 
symptoms of poisoning by, 196 
tests for, 197 

treatment in poisoning by, 87, 196 
Hydroferricyanic acid, 345 
Hydroferrocyanic acid, 344 
Hydrofluoric acid, 148 
Hydrogen, 77 
arsenid, 265 
arseniuretted, 265 
chlorid, 122 
dioxid, 86 
fluorid, 148 
iodid, 147 
peroxid, 86 
phosphid, 187 
phosphoretted, 187 
sulphid, 154 

group reagent, 156 
toxicology of, 157 
sulphuretted, 154 
Hydrolysis, 130, 189, 192, 198, 220, 228, 

427, 535 
Hydrometers, 26 
Hydropyridins, 484 
Hydroquinon, 450, 462 
Hydrosulphuric acid, 156 
Hydroxidion, 131, 135 
Hydroxyl, 82, 131 
Hydruria, 580 
Hygrins, 503 
Hygrometer, 86 
Hyoscin, 503, 506 
Hyoscyamin, 503, 506 
Hyperchlorhydria, 547 
Hypertonic, 96 



642 



INDEX 



Hypobromite method of estimating urea, 

593 
Hypobromites, 144 
Hypochlorhydria, 547 
Hypochlorites, tests for, 141 
Hypochlorosion, 141 
Hypochlorous acid, 140 

oxid, 141 
Hypodermoclysis, 96 
Hyponitrous acid, 175 
Hypophosphites, tests for, 191 
Hypophosphorous acid, 191 
Hyposulphurous acid, 168 
Hypotonic, 96 
Hypoxanthin, 489 



Ichthyol, 458 
Illuminating gas, 100 

oil, 379 
Imido-compounds, 498 
Imins, 498 
Immunity, 522 
Indestructibility, 70 
Indican, 487, 581 
Indicators, 124, 130 
Indigo, 486 

-blue, 486, 581 

disulphacid, 477 

-red, 486, 487 
Indigotin, 486 
Indium, 117 
Indol, 487, 525, 535 
Indophenol reaction, 479 
Indoxyl, 486, 581 
Induced electricity, 53 
Induction coil, 52 
Infection toxins, 522 
Infraproteins, 527, 532 
Inorganic compounds, 64 
Inosite, 437 
Intestinal juice, 559 
Invertase, 438, 538, 557, 560 
Inverted sugar, 436 
Inverting enzyms, 538, 560 
Iodic acid, 147 

Iodids, analytical reactions of, 146 
Iodimetry, 127 
Iodin, 144 

tests for, 147 

tincture of, 145 

toxicology, 146 
detection of, 147 
fatal dose of, 146 
in solution of potassium iodid as 

reagent for alkaloids, 502 
postmortem appearances after, 147 
symptoms of poisoning from, 146 
treatment of poisoning from, 146 
Iodism, 147 
Iodized starch, 146 
Iodoform, 390 



Iodoform, toxicology, 390 
detection of, 391 

postmortem appearances after, 391 
symptoms of poisoning from, 390 
treatment in poisoning by, 390 
Iodol, 483 

Ion formation, first mode, 119 
fourth mode, 340 
second mode, 301 
third mode, 359 
theory, 52, 131 
Ions, 50, 52, 114, 128, 134, 301 
dissociation of, 128 
of cyanids, 135 
of indicators, 130 
of sulphates, 135 
Iridium, 359 
Iron, 337 
acetate, 346 

analytic reactions of, 347 
carbonate, 316 
cast-, 338 
chlorids, 339, 340 
citrate, 344 
dialyzed, 341 
galvanized, 353 
hydroxids, 270, 341 
iodid, 342 
nitrate, 343 
ores, 337 
oxids, 341 
phosphates, 344 

Pig, 33 s 

pyrites, 337 

reduced, 339 

scale, compounds of, 344 

sulphates, 342 

sulphid, 342 

tannate, 347 

tartrate, 344 

toxicology of salts, 346 

trioxid, 339 

wrought, 338 
Isatin, 486, 581 

Isobenzonitril, 388, 477, 478, 498 
Isobutane, 375 

Isocyclic compounds, 448, 483 
Isomerism, no, 200, 376 
Isomorphism, 153 
Isonitril, 388 
Isoquinolin, 488, 503 
Isosmotic, 96 
Isotonic, 96 



Jaborandi, 503, 504 
Jaffe's test, 487 
Jervin, 515 
Joule's unit of energy, 74 



Kainite, 242 
Kairin, 488 



INDEX 



643 



Kalium, 212 
Kaolin, 251 

cataplasm of, 251 
Kelling's test, 552 
Kelp, 141 
Kephir, 440 
Keratin, 528 
Kermes mineral, 291 
Kerosene, 379 
Ketones, 413 
Ketoses, 434 
Kilojoules, 74 
Kinetic theory, 29 
Kippenberger process, 521 
Kjeldahl's method, 365, 595 
Knop's fluid, 592 
Kreatinin, 494, 553 
Krypton, 98 
Kumyss, 439 



Labarraque's fluid, 141 

Lactalbumin, 527, 566 

Lactase, 538 

Lactic acid, 422, 546, 552, 565 

Lactoglobulin, 528, 566 

Lactometer, 569 

Lactoscope, 571 

Lactose, 438, 565 

Laevorotation, 59, 436 

Lamp black, 99 

Lanolin, 558 

Lanthanum, 117, 251 

Lapis infernalis, 335 

Lard, 426 

Latent heat of fusion, 35 

of vaporization, 41 
Laughing-gas, 176 
Law, Avogadro's, 77, 95 

Boyle's, 107 

Charles's, 30, 107 

of chemical combination by volume, 
in 
by weight, 69, 108 
equilibrium, 82, 433 

of the conservation of energy, 70 

of constancy of composition, 69, 108 

of Dalton, 108 

of definite proportions, 70, 108 

of diffusion of gases, 92 

of Dulong and Petit, 35 

of equivalent proportions, 71, 109 

of Faraday, 51 

Gay-Lussac's, 30, in 

Graham's, 92 

Henry's, 91, 123 

Mariotte's, 39 

of mass-action, 82 

Mendelejeff's, 116, 150 

of multiple proportions, 108 

periodic, 116 

of Raoult, 38, 368 



Lead, 320 
acetate, 323 
antidotes to, 324 
carbonate, 322 
chlorid, 322 
chromate, 323, 325 
dioxid, 321 
iodid, 328 
ions of, 321 
nitrate, 322 
oleate, 321 
oxid, 321 
plaster, 321 
red, 321 
sugar of, 323 
sulphate, 322 
toxicology, 323 

detection of, by electrolysis, 328 
in gastric contents and tissues, 329 
in urine, 329 
fatal dose, 324 

period, 324 
poisoning, acute, 324 
causes of, 325 
chronic, 325 

distribution of lead in tissues, 327 
postmortem appearances after, 

3 2 4, 3 2 7 
symptoms of, 323, 325 
poisonous salts of, 323 
quantitative estimation of, 330 
tests for, 328 
treatment in poisoning, acute, 

324 

-water, 322 

white, 322 
Lecithin, 517, 519 
Leclanche cell, 47, 348 
\ Legal's test, 607 
Leucin, 499, 623 
I Leucomains, 517 
i Leucylprolin, 485 

Leukocytes, 561 
I Levulose, 436 
Liebermann's reaction, 526 
Liebig's condenser, 379 
Light, decomposition by, 335 

magnesia, 243 
Ligroin, 379 
Lime, acid phosphate of, 241 

chlorated, 239 

chlorid of, 239 

-kiln, 237 

liniment, 238 

milk of, 238 

quick, 236 

slaked, 237 

superphosphate of, 241 

syrup of, 238 

-water, 238 
Limestone, 237, 240 
Lipases, 429, 538, 545, 557 



644 



INDEX 



Lipolytic enzyms, 538 
Liquefaction of solids, 35 
Liquid air, 108 
Liquids, definition of, 34 
Liquor acidi arsenosi, 267 

ammonii acetatis, 234 

antisepticus, 209 

arseni et hydrargyri iodidi, 287 

calcii bicarbonatis, 240 

chlori compositus, 120 

ferri chloridi, 340 

magnesii citratis, 244 

potassii arsenitis, 267 
citratis, 221 

sodae chlorinatae, 141 

sodii arsenatis, 287 
arsenitis, 287 

phosphatis compositus, 227 
Litharge, 321 
Lithium, 230 

bromid, 230 

carbonate, 230 

citrate, 230 

urate, 230 
Litmus, 123 

solution, 123 
Loadstone, 45 
Lubricating oil, 379 
Lugol's solution, 145 
Lunar caustic, 335 
Lutidin, 485 
Lye, concentrated, 224 
Lymph, 562 
Lymphocytes, 561 
Lysidin, 489 

Lysin, 499, 500, 525, 527 
Lysins, 522 

auto-, 523 

hemo-, 523, 563 

hetero-, 523 

homo-, 523 
Lysol, 460 



Madder, artificial, 474 
Magnalium, 252 
Magnesia, 243 

calcined, 243 

mixture, 586 
Magnesite, 242 
Magnesium, 242 

analytical reactions of, 244 

carbonate, 243, 244 

citrate, 244 

hydroxid, 243 

oxid, 243 

sulphate, 244 
Magnetic iron ore, 45, 341 
Magnetism, 45 
Malachite, 300 
Malleability, 210 
Maltase, 439, 538, 543 



Malting, 395 

Maltose, 83, 395, 439, 537, 538, 543 

Manganates, 348 

Manganese, 347 

analytical reactions of, 350 

black oxid of, 348 

dioxid, 118, 348 

ions of, 348 

oxids of, 348 
Manganic acid, 348 
Manganous carbonate, 349 

hydroxid, 350 

oxid, 118, 348 

sulphate, 348 

sulphid, 348 
Marble, 237, 240 
Margaric acid, 420 
Mariotte's law, 39 
Marsh-gas, 372 
Marsh's test, 279, 295 
Mass, 18 

-action, 82 
Mastication, 542 
Matches, 177 
"Materna, " 573 
Matter, definition of, 17 
Measures, 19 
Meconic acid, 512 
Meerschaum, 242 
Melissic acid, 409 
Melting-points, 34 
Mendelejeff's law, 116, 150 
Menthol, 453 
Mercaptans, 414 
Mercaptols, 415 
Mercurial ointment, 307 

plaster, 307 
Mercuric chlorid, 309 

cyanid, 194, 199 

iodid, 311 

nitrate, 313 

oxid, 308 

potassium iodid, 312, 318' 

sulphate, 313 

sulphid, 312, 318 
Mercurous chlorid, 309 

iodid, 311 

nitrate, 313 

oxid, 308 

salts, tests for, 317 
- sulphate, 313 

sulphid, 312, 318 
Mercury, 306 

ammoniated, 313 

antidotes to, 315 

basic sulphate, 313, 315 

chlorids, 309 

iodids, 311 

ions of, 307 

nitrates, 313 

oleate, 309 

oxids, 308 



INDEX 



645 



Mercury sulphates, 313, 315 
sulphids, 312, 318 
toxicology, 314 

chronic poisoning from, 315 

postmortem appearances after, 

315, 316 
treatment, 315, 316 
detection of, 319 
distribution in tissues, 318 

in urine, 320 
quantitative determination of, 317 
separation of, 319 

by electrolysis, 319 
tests for, 317 
Metabolism, 540 
Meta-compounds, 449 
Metaglobulin, 562 
Metallic elements, 210 
Metallo-cyanides, 199 
Metalloids, 65 
Metals, 210 

classification of, 218, 236 
derivation of names, 117 
melting-points, 34 
separation of, 211 
specific gravity, 211 
valence, 114 
Metamerism, 408 
Metaphosphoric acid, 189 
Meta-position, 449 
Methacetin, 480 
Methane, 372, 376 

series, 372 
Methemoglobin, 530 
Methyl acetanilid, 479 
alcohol, 392 
aldehyd, 406 
amin, 497 
anilin, 478 
benzene, 446, 451 
blue, 477 
chlorid, 384, 385 
hydro xid, 392 
toxicology, 393 
detection of, 394 
fatal dose of, 393 

period of, 393 
symptoms of poisoning by, 393 
treatment in poisoning by, 394 
orange, 124 
salicylate, 469 
Methylated spirit, 393 
Methylene blue, 477 
Methylpiperidin, 485 

chlorid, 384, 385 
Methylthionin hydrochlorid, 477 
Metric system, 20 
Metrology, 17 
Mica, 242 
Michel's paste, 162 
Microcidin, 473 
Microcosmic salt, 235 



Milk, 439, 564 

adulterations of, 210, 568 
analysis of, 564 
casein of, 565 
curds, 566 
modified, 572 
morbid, 564 
Pasteurized, 567 
peptonized, 566 
preservation of, 210, 566, 568 
reaction of, 564 
standards of, 573 
sterilization of, 566 
-sugar, 439, 565 
testing by Adam's method, 576 
by Babcock's method, 574 
by Werner-Schmid method, 574 
Millon's reagent, 457, 500, 527 
Mineral water, 85, 256 
Minium, 321 
Mirbane, oil of, 475 
Mistura cretse, 240 

magnesiae et asafcetidae, 244 
potassi citratis, 221 
Molasses, 438 
Molecular motion, 28 
theory, 28 
weight, in, 368 
Molecule, definition of, 28, 76 
Molisch's test, 434, 473, 500, 527 
Molybdenum, 362 
Molybdic acid, 362 

oxid, 362 
Monazite sand, 361 
Monobasic acids, 162 
Monoclinic system, 152 
Monosaccharids, 434 
Monoses, 434 
Monsel's solution, 342 
Morphin, 503, 512 
acetate, 513 
hydrochlorate, 513 
sulphate, 513 
toxicology, 513 

chronic poisoning by, 514 
description of, 512 
fatal dose of, 514 

period of, 513 
maximum medicinal doses for 

adults, 514 
meconic acid in, 512 
postmortem appearances after, 514 
separation of, from tissues, 521 
symptoms of poisoning by, 513 
tests for, 514 

treatment of poisoning from, 514 
Morpholin, 514 
Mortar, 237 
Mucilage of starch, 440 
Mucin, 531 
Mucoids, 531 
Mucose, 531 



6 4 6 



INDEX 



Mucus, 531 

Mulberry calculus, 592 
Murexid test, 489, 491, 598 
Muriatic acid, 135 
Muscarin, 517, 519 
Muscle sugar, 437 
Mushroom poisoning, 517 
Mustard oil, 539 
Mycoderma aceti, 396, 419 
Mydalein, 517, 519 
Myoalbumin, 527 
Myoglobulin, 528 
Myosin, 528 
Myronic acid, 539 
Myrosin, 539 
Mytilotoxin, 517, 518 



Naphtha, 379 

drunk, 380 
Naphthalene, 445, 471 
Naphthalin, 445, 471 
Naphthol, 473 
beta-, 473 
yellow S, 477 
Naphthosalol, 474 
Narcein, 503, 512 
Narcotin, 512 
Nascent state, 77, 113 
Natrium, 223 
Natural gas, 378 
Neon, 98 
Nepenthe, 512 
Nessler's solution, 312 
Neuridin, 517, 519 
Neurin, 517, 519 
Neutral mixture, 221 
salts, 162 
substances, 124 
Neutralization, 124 
Nickel, 357 
Nicotin, 503, 505 
toxicology, 505 
and pto mains, 517 
chemical tests for, 506 
poisoning from, 505 
symptoms of poisoning, 505 
treatment in poisoning by, 506 
Nicotinic acid, 484, 505 
Niobium, 117 
Niter, 217 

Nitrates, analytical reactions of, 172 
Nitric acid, 169 
toxicology, 171 
detection of, 172 
fatal dose of, 171 

period of, 171 
fumes of, 173 

poisoning, postmortem appear- 
ances after, 171 
symptoms of, 171 
treatment of, 171 



Nitric acid, properties of, 169 
tests for, 172 

ether, 430 
Nitrifying bacteria, 174 
Nitrites, 176 
Nitro-benzene, 475 

toxicology, 475 
detection of, 476 
fatal dose of, 475 
physiologic action of, 475 
postmortem findings after, 475 
treatment in poisoning by, 475 
Nitro-cellulose, 443 
Nitrogen, 97, 169 

combined, 97, 541 

content, 365, 541 

derivatives of benzene, 475 

determination, 365 

dioxid, 174 

monoxid, 176 

oxids, 174 

tetroxid, 175 
Nitrogenous foods, 540 
Nitroglycerin, 431 

tests for, 432 

toxicology of, 432 
Nitrohydrochloric acid, 173 
Nitro-muriatic acid, 173 
Nitrous acid, 175 

ether, 430 

oxid, 176 
Nomenclature, 108 

of acids, 131 

of hydrocarbons, 377 

of ions, 131 
Non-metallic elements, 65 
Nonoses, 434 

Nordhausen sulphuric acid, 162 
Normal salts, 162 

salt solution, 10 1, 225 

solutions, 125 
Notation, 65, 108 
Nucleases, 492, 538 
Nucleic acid, 492, 532 
Nuclein bases, 490 
Nucleinic acid, 532 
Nucleins, 490, 492, 531, 532 

para-, 527, 532 

pseudo-, 527, 532 
Nucleo-albumin, 531 

-histon, 527, 532 

-proteins, 527, 532 
Nutrose, 566 
Nux vomica, 503, 510 
Nylander's reagent, 603 



Oblique system of crystals, 152 
Occluded gas, 81 
Ohm, 49 

Oil, bitter almond, 194, 464 
bone, 484 



INDEX 



647 



Oil, burning, 379 
cotton-seed, 428 
fuel, 379 
illuminating, 379 
olive, 428 
paraffin, 379 
rock, 378 
turpentine, 452 
vitriol, 160 
wintergreen, 467, 469 
Oils, fat, 426 
lubricating, 379 
mustard, 528 
Olenant gas, 381 
Olefins, 381 
Oleic acid, 421 
Olein, 428 
Oleomargarin, 428 
Oliguria, 580 
Olive oil, 428 
Opium, 502 

-alkaloids, 503, 512 
Opsonins, 523 
Orange I, 477 
Orcin test, 607 
Organic analysis, 363 
chemistry, 64, 363 

substances, classification of, 363, 371 
decomposition of, 363 
formation of, in plants, 363 
Ornithin, 499, 525 
Orpiment, 291 
Ortho-compounds, 449 
Orthophosphoric acid, 188 
Ortho-position, 449 
Orthorhombic system of crystals, 154 
Osazone, 434, 481 
Osmium, 359 
Osmosis, 94 
Osmotic pressure, 95 
Ossein, 528 
Ovalbumin, 527 
Oxalates, reactions of, 203 
Oxalic acid, 200, 421 
antidotes to, 203 
toxicology, 201 
detection of, 204 
fatal dose of, 202 

period of, 203 
poisoning, postmortem appear- 
ances, 202 
symptoms of, 201 
treatment of, 203 
properties of, 201 
tests for, 203 
Oxamid, 88, 196 
Oxidases, 538 
Oxidation, energy of, 74 
Oxidimetry, 126 
Oxidizing enzyms, 538, 567 

reagents, 122 
Oxids, 69 



Oxyacids, 139 
Oxybutyric acid, 422 
Oxygen, 65 

derivatives, 392 

in blood, 562 
Oxygenases, 538 
Oxyhemoglobin, 529, 530 
Oxyprolin, 525 
Ozone, 74 
Ozonic ether, 86 



Palladium, 359 
Palmitic acid, 427 
Palmitin, 427 
Pancreas, 555 
Pancreatic juice, 555 
ferments of, 556 
Pancreatin, 557 
Papaverin, 503, 512 
Paper, 442 

parchment-, 442 
Para-compounds, 449 
Paradiazin, 486 
Paraffin, 373, 378, 399 

oil, 379 
Para-formaldehyd, 407 
Paraglobulin, 562 
Paraldehyde 401 

toxicology, 401 
Para-position, 449 
Paraxanthin, 489 
Paris green, 290, 303 
Pasteurization, 396, 567 
Pearlash, 220 
Pearl-white, 342 
Pear oil, 433 
Pearson's solution, 287 
Peat, 99 
Pelletierin, 503 
Pental, 382 
Pentane, 376 
Pentene, 381, 382 
Pentose, 434, 437, 606 
Pepsin, 534, 537, 545, 553, 566 
Peptones, 527, 533, 566 
Peptonized milk, 566 
Perchloric acid, 140 
Periodic acid, 148 
I law, 150 
Permanganates, 348 
Peroxidases, 538, 563 
Petrolatum, 379 
Petroleum, 378 

-ether, 379 

toxicology of, 380 
Pettenkofer's test, 558, 560 
Pewter, 320 
Phagocytes, 523, 562 
Phase rule, 43 
Phenacetin, 479 
Phenanthrene, 474, 504, 512 



6 4 8 



INDEX 



Phenazone, 481 
Phenetidin, 479 
Phenol, 453, 525, 535 

acids, 467 

dihydric, 452, 461 

phthalein, 467 

sulphonic acid, 458 

trihydric, 462 

trinitro, 458 
Phenyl-acetamid, 478 

-acetanilid, 478 

-alanin, 525 

-amin, 476 

hydrate, 453 

hydrazin, 481 

salicylate, 469 
Philosophy, chemical, 108 
Phlorhizin, 443 
Phloroglucin, 463, 549 
Phosgene gas, 192, 386 
Phosphates, analytical reactions of, 189 
Phosphin, 185, 187 

Phosphites, analytical reactions of, 190 
Phosphoglucoproteins, 532 
Phospho-molybdic acid, 189, 362 
Phospho-proteins, 527, 528 
Phosphoretted hydrogen, 187 
Phosphoric acids, 188 

anhydrid, 187 
Phosphorous acid, 190 
Phosphorus, 177 

antidotes to, 181 

chlorids, 191 

content, 367 

detection of, 183 

determination in organic compounds, 

367 
oxids, 187 

red or amorphous, 177 
terhydrid, 187 
toxicology, 178 
fatal dose of, 180 

period of, 180 
necrosis, 182 
phosphorescence of, in hydrogen, 

186 
poisoning, chronic, 182 

postmortem appearances, 181 
symptoms, 180 
treatment of, 181 
postmortem recognition of, 182 
preparations of, 178 
properties of, 177 
quantitative estimation of, 183 
symptoms, 179 
tests for, 183 
treatment, 181 
Photography, 335 
Phthalic acid, 466 
Physical forces, 62 
Picolin, 485 
Picric acid, 458, 611 



Picrotoxin, 521 
Pilocarpin, 503, 504 
Pineapple oil, 433 
Pioscope, 571 
Piperazin, 485, 489 
Piperidein, 485, 503 
Piperidin, 485, 503, 504, 506 
Piperin, 485, 503 
Pipets, 126 
Pitch, 446 

blende, 361 
Plasmon, 566 
Plaster-of -Paris, 241 
Platinum, 359 

and ammonium chlorid, 360 

and potassium chlorid, 360 
black, 360 
chlorids, 360 

colloidal, 87, 360 

sponge, 81, 360 
Plumbago, 99 
Plumbum, 320 
Plummer's pill, 291 
Pneumaturia, 624 
Point, boiling, 369 

flashing, 379 
Polarimeter, 58 

with urine, 61 
Polarized ray, 59 
Polymerism, 408 
Polymorphism, 152 
Polynucleated compounds, 451, 471 
Polypeptids, 524, 527, 534 
Polysaccharids, 440 
Polyuria, 581 
Poppy, 512 
Porosity, 28 
Port wine, 397 
Porter, 397 
Potash, 213 

caustic, 214 
Potassa, 213 

cum calce, 214 

fusa, 214 
Potassium, 212 

acetate, 221 

acid carbonate, 220 
oxalate, 261 
sulphate, 219 
tartrate, 222 

analytic reactions of, 215, 222 

auricyanid, 358 

bicarbonate, 220 

bichromate, 351 

bisulphate, 219 

bitartrate, 222 

bromid, 215 

carbonate, 220 

chlorate, 140, 216 
toxicology of, 216 

chlorid, 215 

chromate, 351 



INDEX 



649 



Potassium citrate, 221 
cyanate, 199 
cyanid, 198 
dichromate, 351 
dioxid, 212 
ferricyanid, 199 
ferrocyanid, 199 
hydrate, 213 
hydrosulphid, 219 
hydroxid, 213 

antidotes for, 275 
toxicology of, 214 
detection of, 215 
fatal dose, 214 
fatal period, 214 

poisoning, postmortem appear- 
ances, 215 
preparations of, 214 
properties of, 212 
symptoms of, 214 
tests for, 215, 222 
iodid, 216 
manganate, 349 
monosulphid, 219 
nitrate, 217 
nitrite, 218 
oxalate, 201 
permanganate, 349 
phenol sulphonate, 458 
picrate, 458 
prussiate, 345 
sodium tartrate, 229 
sulphate, 219 
sulphite, 220 
sulphocyanate, 543 
sulphocyanid, 543 
sulphurated, 219 
tartrate, 222 • 

tests for, 222 
thiocyanate, 543 
Precipitate of mercury, 308 
red, 308 
white, 312 
yellow, 309 
Precipitation of proteins, 526 
Precipitins, 522, 563 
Preliminary examination of urine, 576 
Preservalene, 408, 568 
Preserved milk, 568 
Pressure of air, 107 

of gases, 29, 40 
Prolin, 485, 525 
Proof-spirit, 395 
Propane, 375, 376 
Propene, 381 
Propenyl alcohol, 401 
Propine, 382 
Propionic acid, 417 
Propylene, 381 
Protamins, 527 
Proteases, 537, 545 
Proteids, 524 



Proteins, 524 

coagulated, 533 

compound, 524 

derived, 524 

molecule, 524 

native, 524 

simple, 524 
Proteolytic enzyrns, 537, 545 
Proteoses, 527/533 
Protons, 527 
Prussian blue, 345 
Prussiate of potash, red, 345 

yellow, 344 
Prussic acid, 194 
Pseudo morphin, 514 
Ptomains, 500, 517 

symptoms like alkaloidal poisoning, 
500 

toxicology, 500 
Ptyalin, 537, 543, 556 
Pulvis effervescens compositus, 229 
Purdy's tests, 546, 554 
Purin bases, 489, 535, 539, 599 

bodies, 489-535. 539> 599 
Purinometer, 493 
Pus in urine, 618 
Putrefaction, 396, 525 
Putrescin, 500, 517, 519 
Putty powder, 299 
Pykno meter, 25 
Pyocyanin, 518 
Pyoktannin-blue, 477 
Pvrazin, 486 
Pyridin, 483, 503, 504, 505 

homologues, 485 
Pyrimidin, 491 

bases, 491 

nucleus, 491 
Pyrites, copper, 300 

iron, 337 
Pyrocatechin, 450, 460 
Pyrogallic acid, 462 
Pyrogallol, 422 
Pyroligneous acid, 419 
Pyrolusite, 347 
Pvrophosphoric acid, 188 
Pyroxylin, 442 
Pyrrole, 483, 485 
Pyrrolidin, 485, 503, 505, 506 
Pyuria, 618 



Quadratic system of crystals, 153 

Quantivalence, 114 

Quartz, 205 

Quicklime, 237 

Quicksilver, 306 

Quinidin, 508 

Quinin, 508 

acid sulphate, 509 

citrate of iron and, 344 

sulphate, 509 



650 INDEX 



Quinin, tests for, 509 
Quinol, 450, 462 
Quinolin, 488, 503, 508 



Racemic acid, 423 

Radical, definition of, 194, 377 

list of, 385 
Radio-activity, 109, 247, 249, 251, 361 
Radium, 247 

chlorid, 247 
Ragsky test, 389 
Ratsbane, 266 
Rays, light, 58 
alpha, 248 
Becquerel, 247, 361 
beta, 248 
cathode, 54, 248 
Hertzian, 58 
Lenard, 54 
polarized, 58 

Rontgen, 53, 58, 248, 361 
ultra-red, 58 
ultra-violet, 58 
Reactions, 70, 114 
acid, 124 
alkaline, 125 

amphoteric, 498, 564, 579 
of urine, 579, 584 
Realgar, 291 
Rectified spirit, 396 
Red iodid of mercury, 311 
lead, 321 
oxid of copper, 302 

mercury, 308 
phosphorus, 177 
precipitate, 308 
Reduced iron, 82, 339 
Reducing enzyms, 539 
Reductases, 539 
Reduction by carbon, 100 
by hydrogen, 82 
by sulphur dioxid, 159 
Refrigeration, 396 

of milk, 566 
Regular system of crystals, 152 
Reinsch's test, 271 

for antimony, 277, 295 
for arsenic, 277 
for mercury, 277, 318 
Rennet, 538, 545, 554 
Rennin, 538, 545, 554 
Residue, definition of, 194 
Resorcin, 450, 461, 549 
Reversible processes, 82 
Rheostat, 50 
Rhigolin, 379 
Rhodium, 117 
Ricord's paste, 162 
Riders, 18 

Robert's test for glucose, 604 
Rochelle salt, 229 



Rock-candy, 438 

-crystal, 205 
Rontgen rays, 53, 58, 248, 361 
Rosanilin, 477 

chlorid, 477 
Rubidium, 231 
Ruby, 253 
Rum, 397 
Ruthenium, 117 

Saccharase, 538 

Saccharates, 438 

Saccharic acid, 436 

Saccharids, 434 

Saccharimetry by polariscope, 61, 435, 

438 
Saccharin, 482 
Saccharobioses, 434 
Saccharomyces, 396 
Saccharose, 438, 538 
Sal ammoniac, 234 

prunelle, 217 

sodae, 227 
Saleratus, 221 
Salicin, 443, 467 
Salicylic acid, 467 
Salicyl-sulphonic acid, 615 
Salipyrin, 469 
Saliva, 543 
Salkowski's test, 560 
Salmin, 527 
Salol, 469, 555 
Salophen, 469 
Salt, common, 225 

microcosmic, 235 
Saltpeter, 212, 217 

Chili, 225 
Salts, acid, 163 

definition of, 124, 130 

neutral, 162 

normal, 162 
Sand, 205 

filters, 252 
Saponification, 427 
Sapphire, 253 
Saprin, 517 

Sausage poisoning, 520 
Scale compounds of iron, 344, 425 
Scandium, 117, 251 
Scheele's green, 303 
Schiff's fuchsin reaction, 409 
Schonbein's test, 75 
Schweinfurth's green, 303 
Scleroproteins, 527, 528 
Scopolamin, 506 
Secretin, 555 
Seidlitz powder, 229 
Selenite, 241 
Selenium, 168 
Serin, 500, 525 
Serpentin, 242 



INDEX 



651 



Serum, 527 

albumin, 527, 562, 609 

globulin, 528, 562, 609 
Sherry wine, 397 
Siemen's induction tube, 74 
Silica, 206 
Silicates, 206 
Silicic acid, 206 
Silicium, 205 
Silicon, 205 

chlorid, 207 

dioxid, 206 

fluorid, 207 

hydrid, 207 
Silver, 333 

antidotes to, 336 

bromid, 335 

chlorid, 334 

chromate, 337 

colloidal, 333 

cyanid, 336 

German, 357 

iodid, 337 

ion of, 334 

nitrate, 335 

oxid, 334 

sulphid, 337 

toxicology, 336 
Sinigrin, 443 

Skatol, 487, 500, 525, 535 
Skiagraph, 54 
Slaked lime, 237 
Slate, 251 
Soap, 427 
Soapstone, 242 
Soda, 224 

-ash, 225 

-lime, 237 
Sodium, 78, 223 

amino-phenyl arsenate, 287 

arsenate, 287 

bicarbonate, 228 

bisulphate, 225 

borate, 209 

bromid, 225 

cacodylate, 287 

carbonate, 227 

chlorate, 141 

chlorid, 225 

dimethyl arsenate, 287 

fluorid, 148 

hydrate, 224 

hydroxid, 224 
toxicology, 224 
detection of, 22; 
fatal dose, 224 

period, 224 
poisoning, postmortem appear- 
ances after, 225 
properties of, 224 
symptoms, 224 
tests for, 225, 229 



Sodium hydroxid, toxicology, treatment 
of, 224 

hypobromite, 593 

hypochlorite, 141 

hypophosphite, 191 

hyposulphite, 169 

iodid, 225 

nitrate, 225 

nitroprussid, 346 

peroxid, 224 

phenol sulphonate, 458 

phosphate, 225 

-potassium tartrate, 229 

salicylate, 467 

sesquicarbonate, 228 

silicate, 206 

sulphate, 225 

sulphite, 168 

sulphocarbolate, 458 

thiosulphate, 169 
Solder, soft, 298, 320 
Soldering fluid, 355 
Solids, definition of, 28 
Solution, 89 

of gases in gases, 92 

of gases in liquids, 91 

of liquids in gases, 92 

of liquids in liquids, 91 

of solids in liquids, 90 

-tension, 300 
Solutions, mixed, 134 

saturated, 90 

supersaturated, 91 
Sozolic acid, 458 
Sparteine, 501 
Spasmotoxin, 518 
Specific gravity, 22 

heat, 34 

weight, 22 
Spectroscope, 56 
Spectrum analysis, 56 

of blood, 101, 531, 564 
ol elements, 56 
Spermatozoa in urine, 624 
Spermin, 517 
Spirits of glonoin, 431 

of hartshorn, 233 

of mindererus, 234 

of wine, 395, 397 

proof, 395 

-wood, 396 
Spiritus aetheris nitrosi, 405, 431 

ammonioe, 233 
Squibb's fluid, 593 
Standard solutions, 125 
Standards, dietary, 542 
Stannic acid, 298 

chlorid, 298 

sulphid, 299 
Stannous chlorid, 298 

hydroxid, 298 

sulphid, 299 



652 



INDEX 



Stannum, 298 
Starch, 440 

iodized, 146 

solution, 440 
Steapsin, 428, 429, 557 
Stearic acid, 427 
Stearin, 427 
Stearoptens, 453 
Steel, 337 
Stercobilin, 559 
Stereo-isomerism, 423 
Sterilization, 566 
Stibium, 291 
Stokes' reagent, 529 
Stomach, 544 

contents, 544 

tube, 547 
Strontia, 236, 245 
Strontianite, 245 
Strontium, 245 

analytic reactions of, 245 

carbonate, 245 

oxid, 245 
Structure of flame, 113 
Strychnin, 503, 510 

sulphate, 510 

and ptomains, 517 
description of, 510 
fatal dose of, 510 
period of, 510 
signs of poisoning by, 510 
Sturin, 527 

Subatomic matter, 250 
Sublimation, 85, 150 
Sublimed sulphur, 150 
Substances, properties of, 17 
Substitution, 384 

products of benzene, 449 
Succinic acid, 421 
Succus entericus, 559 
Sucrose, 437 
Sugar, 438 

barley, 438 

beet, 438 

cane-, 437 

detection of, in urine, 600 

fruit, 436 

grape-, 435 

inverted, 436 

of lead, 323 

milk, 438 

muscle-, 437 
Sugars, 433 

compound, 433 

simple, 433 
Sulphaldehyd, 407 
Sulphanion, 135, 160 
Sulphates, reactions of, 166 
Sulphids, reactions of, 156 
Sulphites, reactions of, 159 
Sulphocarbolates, 458 
Sulphocyanates, 190, 345 



Sulphocyanic acid, 190, 345 

Sulphonal, 415 

Sulphone, 415 

Sulphonethylmethane, 415 

Sulphonic acid, 415 

Sulphonmethane, 415 

Sulphophenolates, 458 

Sulphur, 150 
content, 367 

derivatives of paraffins, 414 
determination in organic compounds, 

367 
dioxid, 157, 159 
flowers of, 150 
group, 168 

in proteid molecule, 367 
milk of, 151 
precipitated, 151 
sublimed, 151 
trioxid 160 
water, 256 
Sulphurated antimony, 291 
Sulphuretted hydrogen, 155 
Sulphuric acid, 160 
antidotes to, 165 
dilute, 162 
fuming, 162 
impurities of, 161 
Nordhausen, 162 
toxicology, 163 
detection of, 166 
fatal dose of, 164 

period of, 164 
local external effects of, 163 
poisoning from, 163 

postmortem appearances, 165 
symptoms, 164 
treatment, 165 
properties of, 161 
quantitative test for, 167 
tests for, 166 
ether, 403 
Sulphurous acid, 158 

anhydrid, 157 
Sulphydric acid, 156 
Supercooled water, 43 
Superphosphate of lime, 241 
Sweet spirit of niter, 405, 431 
Symbols', function of, 112 
Synaptase, 539 
Synthesis, 63 
Syntonin, 533, 534 
Syrupus acidi hydriodici, 147 
calcii lactophosphatis, 241 
calcis, 238 



Talc, 251 
Tallow, 426 
Tannic acid, 470 
Tannin, 470 
Tanret's test, 612 



INDEX 



6 53 



Tantalum, 117 
Tar, 445 
Tartar, 423 

cream of, 423 

crude, 423 

emetic, 292 
Tartaric acid, 423 
Tartrates, reactions of, 426 
Taurin, 501, 558 
Taurocholic acid, 558 
Tea, 491 

Teissier's test, 586 
Tellurium, 168 
Tenacity, 28 
Tension of aqueous vapor, 40, 44 

of gases, 29 
Terebene, 453 
Terebenthene, 452 
Terpenes, 452 
Terpin, 451 
Test-breakfast, 547 

-meal, 547 
Tetanin, 518 
Tetanotoxin, 518 
Tetronal, 415, 416 
Thalleioquin, 509 
Thallin, 488 
Thallium, 56, 117 
Thein, 491 

Theobromin, 490, 491 
Theophyllin, 490, 491 
Thermometers, 31, 32 
Thio-alcohols, 414 

-ethers, 414 

-ketones, 414 

-sulphuric acid, 168 
Thorium, 248, 249, 361 
Thrombase, 538, 545, 562 
Thymin, 491 
Thymol, 453 

iodid, 453 
Tin, 298 

-amalgam, 298 

chlorids of, 298 

-plate, 298 

-stone, 298 

toxicology, 299 

symptoms of poisoning from, 299 
tests for, 299 
Tinctura ferri chloridi, 340, 346 
Titanium, 117 
Titration, 126 
Titre, 126 

Tollen's test, 401, 607 
Toluene, 446 
Toluol, 446 
Topfer's reagent, 549 

test, 550 
Toxalbumins, 566 
Toxemia, 522 
Toxins, 520, 566 

food-, 521, 566 



Toxins, infection, 522 
Treacle, 438 
Trichloracetic acid, 420 
Trichloraldehyd, 410 
Trichlormethane, 385 
Triclinic system of crystals, 154 
Triethylamin, 497 
Trimethylamin, 497 
Trinitro-cellulose, 443 

-phenol, 458 
Trional, 414, 416 
Trioses, 434 
Triple phosphate, 587 
Trommer's test, 601 
Tropan alkaloids, 503 
Tropeolin test, 548 
Tropic acid, 506 
Tropin, 506 
Trypsin, 534, 537, 556 
Tryptophan, 500, 525, 556 
Tube-casts in urine, 520 
Tungsten, 117 
Turkey red, 474 
Turmeric test, 569 
Turpentine, 452 
Turpeth mineral, 315 
Type-metal, 320 
Typhotoxin, 518 
Tyrosin, 500, 525, 623 
Tyrotoxicon, 518 



Uffelmann's test, 552 

Ultimate analysis, 365 

Uracil, 491 

Uranin, 89, 461 

Uranium, 248, 249, 361 

Urases, 538, 578 

Urates, 599 

Urea, 193, 200, 492, 495, 499, 535, 57; 

579. 5 8 5> 59 2 
determination of, 593 
nitrate, 496, 592 
Uremia, 595 
Ureometer, 593 
Uric acid, 488, 493, 535, 579, 627 

endogenous and exogenous, 493 
Uricolytic enzyms, 539 
Uricometer, 596 
Urinary calculi, 586, 593, 627 
examination, 576 
sediments, 577, 587, 599, 619 
Urine, 576 

acetone in, 607 
acids in, 584, 608 
air in, 624 
albumin in, 609 

boiling test for, 609 
Esbach's test for, 611 
Heller's test for, 610, 617 
nitric-acid test for, 616 
picric-acid test for, 611 



654 



INDEX 



Urine, albumin in, Purdy's method, 612 

salicyl-sulphonic acid, 615 

Tanret's test for, 612 

trichloracetic acid, 612 
albumose in, 614 
alkapton in, 582 
analysis, 576 
bacteria in, 577, 625 
Bence-Jones' protein, 616 
bile in, 582, 618 
blood in, 616 

calcium oxalate of, 591, 627 
calculi, 627 

centrifuge tests for, 577, 586 
chlorids of, 579, 590 
chyle in, 619 
color, 581 
composition, 579 
creatinin in, 579 
cryoscopy of, 39, 584 
cystin in, 622 

deposits, 577, 587, 599, 619 
diazo-reaction, 626 
epithelium in, 619 
glycuronic acid in, 607 
hematuria, 616 
hippuric acid in, 579 
leucin in, 623 
mucin of, 615 
normal, 579 

nucleo-albumins of, 615 
pentose in, 606 
phosphates of, 579, 585 
polarimetry of, 61 
preservation of, 578 
pus in, 618 
quantity of, 579, 580 
reaction, 579, 584 
retention of, 580 
saccharometer, 548 
secretion, 576 
solids of, 579, 583 
specific gravity, 579, 583 
spermatozoa in, 624 
sugar in, 600 

Bottger's bismuth test for, 603 

Fehling's test for, 602 

fermentation test for, 604 

glycerin-cupric test for, 601 

Nylander's test for, 603 

phenylhydrazin test for, 481, 604 

picric-acid test for, 604 

polariscope test for, 61 

Purdy's test for, 602 
sulphates of, 579, 588 
suppression of, 580 
tube-casts in, 620 

epithelial, 621 

fatty, 622 

granular, 622 

hyaline, 621 

mucous, 621 



Urine, tube-casts waxy in, 621 

tyrosin in, 623 

urates in, 599, 627 

urea in, 496, 579, 592 

uric acid in, 488, 579, 595, 627 
Urinometer, 583 
Urobilin, 559, 581, 618 
Urochrome, 581 
Uroerythrin, 581 
Urorosein, 582 
Urotropin, 498 
Uroxanthin, 497 



Valence, 114, 251 
Valerates, 417 
Valeric acid, 421 
Vanadium, 117 
Vapor density, 26 

tensity, 40, 44 
Vaporization, latent heat of, 42 
Vaselin, 379 

Velocities of reactions, 83 
Veratrin, 515 

reactions of, 516 
Verdigris, 303 
Vermillion, 312 
Vinegar, 419 
Vitellin, 533 
Vitellose, 533 
Vitriol, blue, 303 

green, 342 

oil of, 160 

white, 355 _ 
Volatile alkali, 231 
Volt, 50 

Volumetric analysis, 126 
Vulcanized rubber, 193, 291 



Washing soda, 226, 227 
Water, 83, 256 

alkaline, 256 

alum in, 255 

ammonia in, 262 

-analysis, 260 

bacillus coli in, 261 

biologic test, 261 

carbonated, 256 

chalybeate, 85, 256 

chlorids in, 261 

of crystallization, 83 

distilled, 85 

drinking, 257 

ground, 257 

hard, 258 

maximum density of, 84 

mineral, 85, 256 

organic matter in, 262 

rain, 257 

saline, 256, 

soft, 258 



INDEX 



655 



Water storage, 260 

sulphur, 85, 256 

surface, 257 

well, 258 
Watt, 50 
Waves of ether, 58 

actinic, 58 

heat, 58 

Hertzian, 58 

luminou 
Wax, 429 
Weathering of rocks, 207 
Weight, 18 

atomic, 109 

molecular, no 

specific, 22 
Whey, 566 
Whisky, 397 
White arsenic, 266 

lead, 322 

precipitate, 312 

vitriol, 355 
Widal's test, 523 
Wine, 397 

of antimony, 292 
Winslow's Soothing Syrup, 512 
Wintergreen oil, 469 
Witherite, 245 
Wood-alcohol, 392 

-naphtha, 392 

-spirit, 392, 419 
Wrought iron, 337 



Xaxthix, 489, 490 

bases, 489 
Xantho-proteic reaction, 459, 526 
Xenon, 98 
X-rays, 54 
Xylene, 446, 451 



Xylol, 446, 451 
Xylose, 437 



Yeast, 396 

powders, alum in, 255 
Yellow oxid of mercury, 308 

prussiate of potash, 345 

subsulphate of mercury, 313 

-wash, 308 
Ytterbium, 117, 251 
Yttrium, 117, 251 



Zero, 31 

absolute, 32 
Zinc, 353 

acetate, 354 

antidotes to, 356 

-blende, 353 

carbonate, 354 

chlorid, 355 

ferrocyanid, 357 

fever, 354 

hydroxid, 354 

ion of, 353 

lactate, 354 

oxid, 353 

phenol sulphonate, 458 

phosphid, 354 

sulphate, 355 

toxicology, 355 
detection of, 357 
fatal dose and period of, 356 
tests for, 357 
treatment of poisoning from, 356 

-white, 354 
Zirconium, 117 
Zymase, 396 
Zymogen, 556 



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animals, thus leading to the development of many new features. The text is pur- 
posely concise, the technic being presented very clearly by the numerous practical 
illustrations, all made from actual operations done either upon the animal or the 
human being. As the success of gastro-intestinal surgery depends upon an accur- 
ate knowledge of the elementary steps, a thorough account of repair is included. 

New York State Journal of Medicine 

" The illustrations are so good that one scarcely needs the text to elucidate the steps of 
the operations described. The work represents the best surgical knowledge and skill." 



DaCosta's Modern Surgery 

Modern Surgery — General and Operative. By John Chalmers 
DaCosta, M. D., Professor of the Principles of Surgery and of Clinical 
Surgery in the Jefferson Medical College, Philadelphia. Octavo of 1283 
pages, with 872 illustrations. Cloth, $5.50 net ; Half Morocco, $7.00 net. 

RECENTLY ISSUED— THE NEW (5th) EDITION 

For this new fifth edition the work has been entirely rewritten and reset. One 
hundred and fifty new illustrations have been added ; and the work has been en- 
larged by the addition of two hundred pages. To keep the book of a size to handle 
conveniently, a thinner but high-grade paper has been used. DaCosta's Surgery 
in this edition will more than maintain the reputation already won. 

Boston Medical and Surgical Journal 

" We commend the book, as we have previously commended it, to surgeons and to students 
as the most satisfactory one-volume contemporaneous treastise on surgery published in this 
country." 



SURGERY AND ANATOMl 



Schultze and Stewart's 
Topographic Anatomy 

Atlas and Text=Book of Topographic and Applied Anatomy. By 

Prof. Dr. O. Schultze, of Wiirzburg-. Edited, with additions, by 
George D. Stewart, M.D., Professor of Anatomy and Clinical Sur- 
gery, University and Bellevue Hospital Medical College, N. Y. Large 
quarto of 189 pages, with 25 colored figures on 22 colored lithographic 
plates, and 89 text-cuts, 60 in colors. Cloth, $5.50 net. 

RECENTLY ISSUED 

It was Professor Schultze' s special aim, in preparing this work, to produce a 
Text-Book and Atlas, not for the anatomist alone, but more particularly for the 
general practitioner. The value of the knowledge of topographic anatomy in bed- 
side diagnosis is emphasized throughout the book. The many colored lithographic 
plates are exceptionally excellent. 

Arthur Dean Bevan. M. D., Professor of Surgery in Rush Medical College, Chicago. 

" I regard Schultze and Stewart's Topographic and Applied Anatomy as a very admirable 
work, for students especially, and I find the plates and the text excellent." 

Sobotta and McMurrich's 
Human Anatomy 

Atlas and Text=Book of Human Anatomy. In Three Volumes. By 
J. Sobotta, M.D., of Wiirzburg. Edited, with additions, by J. Playfair 
McMurrich, A. M., Ph. D., Professor of Anatomy, University of Mich- 
igan, Ann Arbor. Three large quartos, each containing about 250 
pages of text and over 300 illustrations, mostly in colors. Per volume: 
Cloth, $6. 00 net; Half Morocco, $7.50 net. 

VOLUME III NOW READY— COMPLETING THE WORK 

The great advantage of this over other similar works lies in the large number 
of magnificent lithographic plates which it contains, without question the best that 
have ever been produced in this field. They are accurate and beautiful reproduc- 
tions of the various anatomic parts represented. 

Edward Martin, M.D., Professor of Clinical Surgery, University of Pennsylvania. 

"This is a piece of bookmaking which is truly admirable, with plates and text so well 
chosen and so clear that the work is most useful to the practising surgeon." 



io SAUNDERS' BOOKS ON 

Eisendrath's 
Surgical Diagnosis 

A Text=Book of Surgical Diagnosis. By Daniel N. Eisendrath, 
M.D., Adjunct Professor of Surgery in the College of Physicians and 
Surgeons, Chicago. Octavo of 775 pages, with 482 entirely new and 
original text-illustrations and some colored plates. Cloth, $6.50 net; 
Half Morocco, $8.00 net. 

RECENTLY ISSUED 
WITH 482 ORIGINAL ILLUSTRATIONS 

Of first importance in every surgical condition is a correct diagnosis, for upon 
this depends the treatment to be pursued ; and the two — diagnosis and treatment — 
constitute the most practical part of practical surgery. Dr. Eisendrath takes up 
each disease and injury amenable to surgical treatment, and sets forth the means 
of correct diagnosis in a systematic and comprehensive way. Definite directions 
as to methods of examination are presented clearly and concisely, providing for 
all contingencies that might arise in any given case. Each illustration indi- 
cates precisely how to diagnose the condition considered. 

Surgery, Gynecology, and Obstetrics 

"The book is one which is well adapted to the uses of the practising surgeon who desires 
information concisely and accurately given. . . . Nothing of diagnostic importance is omitted, 
vet the author does not run into endless detail." 



Eisendrath's Clinical Anatomy 

A Text=Book of Clinical Anatomy. By Daniel N. Eisendrath, 
A.B., M.D., Adjunct Professor of Surgery in the College of Physicians 
and Surgeons, Chicago. Octavo of 535 pages, illustrated. Cloth, 
$5.00 net; Half Morocco, $6.50 net. 

RECENTLY ISSUED— THE NEW (2d) EDITION 

This new anatomy discusses the subject from the clinical standpoint. A por- 
tion of each chapter is devoted to the examination of the living through palpation 
and marking of surface outlines of landmarks, vessels, nerves, thoracic and 
abdominal viscera. The illustrations are from new and original drawings and 
photographs. This edition has been carefully revised. 

Medical Record, New York 

"A special recommendation for the figures is that they are mostly original and were 
made for the purpose in view. The sections of joints and trunks are those of formalinized 
cadavers and are unimpeachable in accuracy." 



SURGER Y AND ANA TOMY i 1 

Irvterr^atioiAal 
Text-Book of Surgery 

SECOND EDITION, THOROVGHLY REVISED AND ENLARGED 

The International Text=Book of Surgery. In two volumes. By 
American and British authors. Edited by J. Collins Warren, M.D., 
LL.D., F.R.C.S. (Hon.), Professor of Surgery, Harvard Medical 
School ; and A. Pearce Gould, M.S., F.R.C.S., of London, England. — 
Vol. I. General and Operative Surgery. Royal octavo, 975 pages, 
461 illustrations, 9 full-page colored plates. — Vol. II. Special or 
Regional Surgery. Royal octavo, 1 122 pages, 499 illustrations, and 
8 full-page colored plates. 

Per volume : Cloth, $5.00 net; Half Morocco, $6.50 net. 

American text-book of Surgery 

FOURTH EDITION, RECENTLY ISSUED— OVER 43,000 COPIES 

American Text=Book of Surgery. Edited by W. W. Keen, M.D., 

LL.D., Hox. F.R.C.S., Eng. and Edix., and J. William White, M. D., 
Ph.D. Octavo, 1363 pages, 551 text-cuts and 39 colored and half-tone 
plates. Cloth, 3 7- 00 net; Half Morocco, 58.50 net. 

Robson and Cammidge 
on the Pancreas 

The Pancreas : its Surgery and Pathology. By A. W. Mayo Rob- 
son, F. R. C. S., of London, England ; and P. J. Cammidge, F. R. C. S., of 
London, England. Octavo of 546 pages, illustrated. Cloth, $5.00 net ; Half 
Morocco, $6.50 net. 

RECENTLY ISSUED 

This new work, upon one of the most widely discussed subjects of the times, 
represents the original investigations of these eminent authorities. It takes up 
Anatomy, Embryology, Histology, Physiology, Pathology, Symptomatology, and 
Injuries and Diseases, and there are special chapters on Chemical Pathology and 
Diabetes. The text is illustrated. 



12 SAUNDERS' BOOKS ON 



American Illustrated Dictionary £%$&£ 

The American Illustrated Medical Dictionary. With tables 
of Arteries, Muscles, Nerves, Veins, etc. ; of Bacilli, Bacteria, etc. • 
Eponymic Tables of Diseases, Operations, Stains, Tests, etc. By W. A. 
Newman Dorland, M.D. Large octavo, 840 pages. Flexible leather, 
$4.50 net; with thumb index, $5.00 net. 

Howard A. Kelly, M.D., Professor of Gynecology, Johns Hopkins University, Baltimore. 

"Dr. Dorland's dictionary is admirable. It is so well gotten up and of such con- 
venient size. No errors have been found in my use of it." 

Golebiewski and Bailey's Accident Diseases 

Atlas and Epitome of Diseases Caused by Accidents. By Dr. 

Ed. Golebiewski, of Berlin. Edited, with additions, by Pearce Bailey, 
M.D. Consulting Neurologist to St. Luke's Hospital, New York City. 
With 71 colored figures on 40 plates, 143 text-cuts, and 549 pages of 
text. Cloth, $4.00 net. In Saunders' Hand- Atlas Series. 

Helferich and Bloodgood on Fractures 

Atlas and Epitome of Traumatic Fractures and Dislocations 

By Prof. Dr. H. Helferich, of Greifswald, Prussia Edited, with ad- 
ditions, by Joseph C. Bloodgood, M. D., Associate in Surgery, Johns 
Hopkins University, Baltimore. 216 colored figures on 64 lithographic 
plates, 190 text-cuts, and 353 pages of text. Cloth, $3.00 net. In Saun- 
ders' Atlas Series. 

Sultan and Coley on Abdominal Hernias 

Atlas and Epitome of Abdominal Hernias. By Pr. Dr. G. Sul- 
tan, ofGottingen. Edited, with additions, by Wm. B. Coley, M. D., 
Clinical Lecturer and Instructor in Surgery, Columbia University, New 
York. 119 illustrations, 36 in colors, and 277 pages of text. Cloth, 
$3.00 net. In Saunders' Hand- Atlas Series. 

Warren's Surgical Pathology |S* 

Surgical Pathology and Therapeutics. By J. Collins Warren, 
M.D., LL.D., F.R.C.S. (Hon.), Professor of Surgery, Harvard Medical 
School. Octavo, 873 pages; 136 illustrations, ^ i n colors. Cloth, 
$5.00 net; Half Morocco, $6.50 net. 

Zuckerkandl and DaCosta's Surgery %%Zt 

Atlas and Epitome of Operative Surgery. By Dr. O. Zucker- 
kandl, of Vienna. Edited, with additions, by J. Chalmers DaCosta, 
M,D., Professor of the Principles of Surgery and Clinical Surgery, Jeffer- 
son Medical College, Phila. 40 colored plates, 278 text-cuts, and 410 
pages of text. Cloth, $3.50 net. In Saunders' Atlas SeiHes. 



SURGERY AXD ANATOMY 13 

Lewis' Anatomy and Physiology for Nurses 

Just Issued— New (2d) Edition 

Anatomy and Physiology for Nurses. By LeRoy Lewis, M. D., Surgeon 
to and Lecturer on Anatomy and Physiology for Nurses at the Lewis Hospital, 
Bay City, Michigan. i2mo, 347 pages, with 146 illustrations. Cloth, $1.75 net. 

A demand for such a work as this, treating the subjects from the nurse's point of view, has 
long existed. Dr. Lewis has based the plan and scope of this work on the methods em- 
ployed by him in teaching these branches, making the text unusually simple and clear. 

Nurses Journal of the Pacific Co&.st 

" It is not in any sense rudimentary, but comprehensive in its treatment of the subjects in hand." 

McClellan's Art Anatomy 

Anatomy in Its Relation to Art. By George McClellan, M.D., Professor 
of Anatomy, Pennsylvania Academy of the Fine Arts. Quarto volume, 9 by 
12^ inches, with 338 original drawings and photographs, and 260 pages of 
text. Dark blue vellum, $10.00 net ; Half Russia, 512.50 net. 

Howard Pyle, in the Philadelphia Medical Journal 

"The book is one of the best and the most thorough text-books of artistic anatomy which it has been 
the writer's fortune to fall upon, and, as a text-book, it ought to make its way into the field for which 
it is intended." 

Seilll OI1 TlimOrS Second Revised Edition 

Pathology and Surgical Treatment of Tumors. By Nicholas Senn, 
M.D., Ph.D., LL.D., Professor of Surgery, Rush Medical Couege, Chicago. 
Handsome octavo, 718 pages, with 478 engravings, including 12 full-page 
colored plates. Cloth, S5.00 net ; Sheep or Half Morocco, $6.50 net. 

Senn Practical Surgery £&£*£££ 

Practical Surgery. A Work for the General Practitioner. By Nicholas 

Senn, M. D., Ph. D., LL. D., Professor of Surgery in Rush Medical College, 

Chicago. Octavo of 11 33 pages, with 650 illustrations, many in colors. 

Cloth, s6. 00 ; Sheep or Half Morocco, $7.50 net. Sold by Subscription. 

"It is of value not only as presenting comprehensively the most advanced teachings of 
modern surgery in the subjects which it takes up, but also as a record of the matured opin- 
ions and practice of an accomplished and experienced surgeon." — Annals of Surgery. 

Macdonald's Diagnosis and Treatment 

A Clinical Text=Book of Surgical Diagnosis and Treatment. By J. W. 

Macdonald, M.D. Edin., F.R.C.S. lEdin.), Professor Emeritus of the Prac- 
tice of Surgery and of Clinical Surgery in Hamline University, Minneapolis. 
Octavo, 798 pages, illus. Cloth, S5.00 net; Sheep or Half Mor. , $6.50 net. 



14 SAUNDERS' BOOKS ON 

Haynes* Anatomy 

A Manual of Anatomy. By Irving S. Haynes, M.D., Professor of Prac- 
tical Anatomy, Cornell , University Medical College. Octavo, 680 pages, 
with 42 diagrams and 134 full-page half-tones. Cloth, $2.50 net. 

" This book is the work of a practical instructor— one who knows by experience the require- 
ments of the average student, and is able to meet these requirements in a very satisfactory 
way." — The Medical Record, New York. 

American Pocket Dictionary Fifth %£*££ 

The American Pocket Medical Dictionary. Edited by W. A. Newman 

Dorland, A.M., M.D., Assistant Obstetrician, Hospital of the University of 
Pennsylvania, etc. 566 pages. Full leather, limp, with gold edges, $1.00 
net; with patent thumb index, $1.25 net. 

" I am struck at once with admiration at the compact size and attractive exterior. I can recom- 
mend it to our students without reserve."— James W. Holland, M.D.. Prof essor of Medical 
Chemistry and Toxicology, at the Jefferson Medical College, Philadelphia. 

Beck's Fractures 

Fractures. By Carl Beck, M.D., Professor of Surgery, New York Post- 
graduate Medical School and Hospital. With an Appendix on the Practical 
Use of the Rontgen Rays. 335 pages, 170 illustrations. Cloth, $3.50 net. 

" The use of the rays with its technic is fully explained, and the practical points are brought out 
with a thoroughness that merits high praise." — The Medical Record, New York. 

Barton and Wells' Medical Thesaurus 

A Thesaurus of Medical Words and Phrases. By Wilfred M. Barton, 
M. D., Assistant to Professor of Materia Medica and Therapeutics, and Lec- 
turer on Pharmacy, Georgetown University, Washington, D. C ; and Walter 
A. Wells, M. D., Demonstrator of Laryngology, Georgetown University, 
Washington, D. C i2mo of 534 pages. Flexible leather, $2.50 net ; with 
thumb index, $3.00 net. 

Stoney's Surgical Technic Ne^?2% y E<iition 

Bacteriology and Surgical Technic for Nurses. By Emily M. A. Stoney, 
Superintendent at the Carney Hospital, South Boston, Mass. Revised by 
Frederic R. Griffith, M. D., Surgeon, of New York. i2mo, 266 pages, 
illustrated. $1-5° net 

" These subjects are treated most accurately and up to date, without the superfluous reading 
which is so often employed. . . . Nurses will find this book of the greatest value. — 
Trained Nurse and Hospital Review. 

Grant on Face, Mouth, and Jaws 

A Text=Book of the Surgical Principles and Surgical Diseases of the 
Face, Mouth, and Jaws. For Dental Students. By H. Horace Grant, 
A.M., M.D., Professor of Surgery and of Clinical Surgery, Hospital College 
of Medicine. Octavo of 231 pages, with 68 illustrations. Cloth, $2.50 net. 

" The language of the book is simple and clear. ... We recommend the work to those foi 
whom it is intended."— Philadelphia Medical Journal. 



SURGER Y AND ANA TOMY 1$ 

Preiswerk and Warren's Dentistry Recently issued 

Atlas and Epitome of Dentistry. By Prof. G. Preiswerk, of Basil. Ed- 
ited, with additions, by George W. Warren, D.D.S., Professor of Operative 
Dentistry, Pennsylvania College of Dental Surgery, Philadelphia. With 44 
lithographic plates, 152 text-cuts, and 343 pages of text. Cloth, $3.50 net. 
In Saunders Atlas Series. 

" Nowhere in dental literature have we ever seen illustrations which can begin to compare 
with the exquisite colored plates produced in this volume." — Dental Review. 

Beck's Surgical Asepsis 

A Manual of Surgical Asepsis. By Carl Beck, M. D. 306 pages ; 65 
text-illustrations and 12 full-page plares. Cloth, $1.25 net. 

**The book is well written. The data are clearly and concisely given. The facts are well 
arranged. It is well worth reading to the student, the physician in general practice, and the 
surgeon." — Boston Medical and Surgical Journal. 

Griffith's Hand-Book of Surgery Recently issued 

A Manual of Surgery. By Frederic R. Griffith, M. D., Surgeon to the 
Bellevue Dispensary, New York City. i2mo of 579 pages, with 417 illus- 
trations. Flexible leather, $2.00 net. 

" Well adapted to the needs of the student and to the busy practitioner for a hasty review of important 
points in surgery." — American Medicine. 

Serin's Syllabus of Surgery 

A Syllabus of Lectures on the Practice of Surgery. Arranged in con- 
formity with "American Text-Book of Surgery." By Nicholas Sknn, 
M.D., Ph.D., LL.D., Professor of Surgery, Rush Medical College, Chicago. 

Cloth, $1.50 net. 

" The author has evidently spared no pains in making his Syllabus thoroughly comprehensive, 
and has added new matter and alluded to the most recent authors and operations. Full refer- 
ences are also given to all requisite details of surgical anatomy and pathology." — British Medi- 
cal Journal. 

Keen's Addresses and Other Papers Recently issued 

Addresses and Other Papers. Delivered by William W. Keen, M. D., 
LL.D., F. R. C. S. (Hon.), Professor of the Principles of Surgery and of Clin- 
ical Surgery, Jefferson Medical College, Philadelphia. Octavo volume of 
441 pages, illustrated. Cloth, $3.75 net. 

Keen on the Surgery of Typhoid 

The Surgical Complications and Sequels of Typhoid Fever. By Wm. W. 

Keen, M.D., LL.D., F.R.C.S. (Hon.), Professor of the Principles of Surgery 
and of Clinical Surgery, Jefferson Medical College, Philadelphia, etc. 
Octavo volume of 386 pages, illustrated. Cloth, $3.00 net. 

" Every surgical incident which can occur during or after typhoid fever is amply discussed and 
fully illustrated by cases. . . . The book will be useful both to the surgeon and physician. - 
The Practitioner. London. 



** SURGER Y AND ANA TOMY 



Moore's Orthopedic Surgery 

A Manual of Orthopedic Surgery. By James E. Moore, M.D., Professor 
of Clinical Surgery, University of Minnesota, College of Medicine and Surgery. 
Octavo of 356 pages, handsomely illustrated. Cloth, $2.50 net. 

" Ju e h °P k is emine "tly practical. It is a safe guide in the understanding- and treatment ot 
orthopedic cases. Should be owned by every surgeon and practitioner."— Annals of Surgery. 

Fowler'S Operating Room Recently Issued-New (2d) Edition 

The Operating Room and the Patient, By Russell S. Fowler, M. D., 
Surgeon to the German Hospital, Brooklyn, New York. Octavo of 284 
pages, illustrated. Cloth, #2.00 net. 

Dr. Fowler has written his book for surgeons, nurses assisting at an operation, internes, 
and all others whose duties bring them into the operating room. It contains explicit 
directions for the preparation of material, instruments needed, position of patient, etc., 
all beautifully illustrated. 

Nancrede's Principles of Surgery i^T^d) EditSn 

Lectures on the Principles of Surgery. By Chas. B. Nancrede, M.D., 
LL.D., Professor of Surgery and of Clinical Surgery, University of Michigan, 
Ann Arbor. Octavo, 407 pages, illustrated. Cloth, $2.50 net. 

" We can strongly recommend this book to all students and those who would see something 
of the scientific foundation upon which the art of surgery is built." — Quarterly Medical Journal, 
Sheffield, England. 

Nancrede's Essentials of Anatomy. tZ&%£* 

Essentials of Anatomy, including the Anatomy of the Viscera. By Chas. 

B. Nancrede, M.D., Professor of Surgery and of Clinical Surgery, University 

of Michigan, Ann Arbor. Crown octavo, 388 pages ; 180 cuts. With an 

Appendix containing over 60 illustrations of the osteology of the body. Based 

on Gray s Anatomy. Cloth, $1. 00 net. In Saunders Question Compends. 

" The questions have been wisely selected, and the answers accurately and concisely given." — 
University Medical Magazine. 

Martin's Essentials of Surgery. Seve Revi^" i<m 

Essentials of Surgery. Containing also Venereal Diseases, Surgical Land- 
marks, Minor and Operative Surgery, and a complete description, with illus- 
trations, of the Handkerchief and Roller Bandages. By Edward Martin, 
A.M., M.D., Professor of Clinical Surgery, University of Pennsylvania, etc. 
Crown octavo, 338 pages, illustrated. With an Appendix on Antiseptic Sur- 
gery, etc. Cloth, $i.oo net. In Saunders Question Commends. 

" Written to assist the student, it will be of undoubted value to the practitioner, containing as it 
does the essence of surgical work." — Boston Medical and Surgical Journal. 

Martin's Essentials of Minor Surgery, Band- 
aging, and Venereal Diseases. Sec °Ed*on Vised 

Essentials of Minor Surgery, Bandaging, and Venereal Diseases. By 

Edward Martin, A.M., M.D., Professor of Clinical Surgery, University of 
Pennsylvania, etc. Crown octavo, 166 pages, with 78 illustrations. 

Cloth, $1.00 net. In Saunders' Question Compends. 

" The best condensation of the subjects of which it treats yet placed before the profession, "— 

The Medical News, Philadelphia. 



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